Commit | Line | Data |
---|---|---|
fbb9ce95 IM |
1 | /* |
2 | * kernel/lockdep.c | |
3 | * | |
4 | * Runtime locking correctness validator | |
5 | * | |
6 | * Started by Ingo Molnar: | |
7 | * | |
4b32d0a4 PZ |
8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
fbb9ce95 IM |
10 | * |
11 | * this code maps all the lock dependencies as they occur in a live kernel | |
12 | * and will warn about the following classes of locking bugs: | |
13 | * | |
14 | * - lock inversion scenarios | |
15 | * - circular lock dependencies | |
16 | * - hardirq/softirq safe/unsafe locking bugs | |
17 | * | |
18 | * Bugs are reported even if the current locking scenario does not cause | |
19 | * any deadlock at this point. | |
20 | * | |
21 | * I.e. if anytime in the past two locks were taken in a different order, | |
22 | * even if it happened for another task, even if those were different | |
23 | * locks (but of the same class as this lock), this code will detect it. | |
24 | * | |
25 | * Thanks to Arjan van de Ven for coming up with the initial idea of | |
26 | * mapping lock dependencies runtime. | |
27 | */ | |
a5e25883 | 28 | #define DISABLE_BRANCH_PROFILING |
fbb9ce95 IM |
29 | #include <linux/mutex.h> |
30 | #include <linux/sched.h> | |
31 | #include <linux/delay.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/kallsyms.h> | |
37 | #include <linux/interrupt.h> | |
38 | #include <linux/stacktrace.h> | |
39 | #include <linux/debug_locks.h> | |
40 | #include <linux/irqflags.h> | |
99de055a | 41 | #include <linux/utsname.h> |
4b32d0a4 | 42 | #include <linux/hash.h> |
81d68a96 | 43 | #include <linux/ftrace.h> |
b4b136f4 | 44 | #include <linux/stringify.h> |
d588e461 | 45 | #include <linux/bitops.h> |
fbb9ce95 IM |
46 | #include <asm/sections.h> |
47 | ||
48 | #include "lockdep_internals.h" | |
49 | ||
a8d154b0 | 50 | #define CREATE_TRACE_POINTS |
ad8d75ff | 51 | #include <trace/events/lockdep.h> |
a8d154b0 | 52 | |
f20786ff PZ |
53 | #ifdef CONFIG_PROVE_LOCKING |
54 | int prove_locking = 1; | |
55 | module_param(prove_locking, int, 0644); | |
56 | #else | |
57 | #define prove_locking 0 | |
58 | #endif | |
59 | ||
60 | #ifdef CONFIG_LOCK_STAT | |
61 | int lock_stat = 1; | |
62 | module_param(lock_stat, int, 0644); | |
63 | #else | |
64 | #define lock_stat 0 | |
65 | #endif | |
66 | ||
fbb9ce95 | 67 | /* |
74c383f1 IM |
68 | * lockdep_lock: protects the lockdep graph, the hashes and the |
69 | * class/list/hash allocators. | |
fbb9ce95 IM |
70 | * |
71 | * This is one of the rare exceptions where it's justified | |
72 | * to use a raw spinlock - we really dont want the spinlock | |
74c383f1 | 73 | * code to recurse back into the lockdep code... |
fbb9ce95 | 74 | */ |
74c383f1 IM |
75 | static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
76 | ||
77 | static int graph_lock(void) | |
78 | { | |
79 | __raw_spin_lock(&lockdep_lock); | |
80 | /* | |
81 | * Make sure that if another CPU detected a bug while | |
82 | * walking the graph we dont change it (while the other | |
83 | * CPU is busy printing out stuff with the graph lock | |
84 | * dropped already) | |
85 | */ | |
86 | if (!debug_locks) { | |
87 | __raw_spin_unlock(&lockdep_lock); | |
88 | return 0; | |
89 | } | |
bb065afb SR |
90 | /* prevent any recursions within lockdep from causing deadlocks */ |
91 | current->lockdep_recursion++; | |
74c383f1 IM |
92 | return 1; |
93 | } | |
94 | ||
95 | static inline int graph_unlock(void) | |
96 | { | |
381a2292 JP |
97 | if (debug_locks && !__raw_spin_is_locked(&lockdep_lock)) |
98 | return DEBUG_LOCKS_WARN_ON(1); | |
99 | ||
bb065afb | 100 | current->lockdep_recursion--; |
74c383f1 IM |
101 | __raw_spin_unlock(&lockdep_lock); |
102 | return 0; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Turn lock debugging off and return with 0 if it was off already, | |
107 | * and also release the graph lock: | |
108 | */ | |
109 | static inline int debug_locks_off_graph_unlock(void) | |
110 | { | |
111 | int ret = debug_locks_off(); | |
112 | ||
113 | __raw_spin_unlock(&lockdep_lock); | |
114 | ||
115 | return ret; | |
116 | } | |
fbb9ce95 IM |
117 | |
118 | static int lockdep_initialized; | |
119 | ||
120 | unsigned long nr_list_entries; | |
d588e461 | 121 | struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
fbb9ce95 | 122 | |
fbb9ce95 IM |
123 | /* |
124 | * All data structures here are protected by the global debug_lock. | |
125 | * | |
126 | * Mutex key structs only get allocated, once during bootup, and never | |
127 | * get freed - this significantly simplifies the debugging code. | |
128 | */ | |
129 | unsigned long nr_lock_classes; | |
130 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; | |
131 | ||
f82b217e DJ |
132 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
133 | { | |
134 | if (!hlock->class_idx) { | |
135 | DEBUG_LOCKS_WARN_ON(1); | |
136 | return NULL; | |
137 | } | |
138 | return lock_classes + hlock->class_idx - 1; | |
139 | } | |
140 | ||
f20786ff PZ |
141 | #ifdef CONFIG_LOCK_STAT |
142 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); | |
143 | ||
c7e78cff | 144 | static int lock_point(unsigned long points[], unsigned long ip) |
f20786ff PZ |
145 | { |
146 | int i; | |
147 | ||
c7e78cff PZ |
148 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
149 | if (points[i] == 0) { | |
150 | points[i] = ip; | |
f20786ff PZ |
151 | break; |
152 | } | |
c7e78cff | 153 | if (points[i] == ip) |
f20786ff PZ |
154 | break; |
155 | } | |
156 | ||
157 | return i; | |
158 | } | |
159 | ||
160 | static void lock_time_inc(struct lock_time *lt, s64 time) | |
161 | { | |
162 | if (time > lt->max) | |
163 | lt->max = time; | |
164 | ||
165 | if (time < lt->min || !lt->min) | |
166 | lt->min = time; | |
167 | ||
168 | lt->total += time; | |
169 | lt->nr++; | |
170 | } | |
171 | ||
c46261de PZ |
172 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
173 | { | |
174 | dst->min += src->min; | |
175 | dst->max += src->max; | |
176 | dst->total += src->total; | |
177 | dst->nr += src->nr; | |
178 | } | |
179 | ||
180 | struct lock_class_stats lock_stats(struct lock_class *class) | |
181 | { | |
182 | struct lock_class_stats stats; | |
183 | int cpu, i; | |
184 | ||
185 | memset(&stats, 0, sizeof(struct lock_class_stats)); | |
186 | for_each_possible_cpu(cpu) { | |
187 | struct lock_class_stats *pcs = | |
188 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
189 | ||
190 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) | |
191 | stats.contention_point[i] += pcs->contention_point[i]; | |
192 | ||
c7e78cff PZ |
193 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
194 | stats.contending_point[i] += pcs->contending_point[i]; | |
195 | ||
c46261de PZ |
196 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
197 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); | |
198 | ||
199 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); | |
200 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); | |
96645678 PZ |
201 | |
202 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) | |
203 | stats.bounces[i] += pcs->bounces[i]; | |
c46261de PZ |
204 | } |
205 | ||
206 | return stats; | |
207 | } | |
208 | ||
209 | void clear_lock_stats(struct lock_class *class) | |
210 | { | |
211 | int cpu; | |
212 | ||
213 | for_each_possible_cpu(cpu) { | |
214 | struct lock_class_stats *cpu_stats = | |
215 | &per_cpu(lock_stats, cpu)[class - lock_classes]; | |
216 | ||
217 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); | |
218 | } | |
219 | memset(class->contention_point, 0, sizeof(class->contention_point)); | |
c7e78cff | 220 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
c46261de PZ |
221 | } |
222 | ||
f20786ff PZ |
223 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
224 | { | |
225 | return &get_cpu_var(lock_stats)[class - lock_classes]; | |
226 | } | |
227 | ||
228 | static void put_lock_stats(struct lock_class_stats *stats) | |
229 | { | |
230 | put_cpu_var(lock_stats); | |
231 | } | |
232 | ||
233 | static void lock_release_holdtime(struct held_lock *hlock) | |
234 | { | |
235 | struct lock_class_stats *stats; | |
236 | s64 holdtime; | |
237 | ||
238 | if (!lock_stat) | |
239 | return; | |
240 | ||
241 | holdtime = sched_clock() - hlock->holdtime_stamp; | |
242 | ||
f82b217e | 243 | stats = get_lock_stats(hlock_class(hlock)); |
f20786ff PZ |
244 | if (hlock->read) |
245 | lock_time_inc(&stats->read_holdtime, holdtime); | |
246 | else | |
247 | lock_time_inc(&stats->write_holdtime, holdtime); | |
248 | put_lock_stats(stats); | |
249 | } | |
250 | #else | |
251 | static inline void lock_release_holdtime(struct held_lock *hlock) | |
252 | { | |
253 | } | |
254 | #endif | |
255 | ||
fbb9ce95 IM |
256 | /* |
257 | * We keep a global list of all lock classes. The list only grows, | |
258 | * never shrinks. The list is only accessed with the lockdep | |
259 | * spinlock lock held. | |
260 | */ | |
261 | LIST_HEAD(all_lock_classes); | |
262 | ||
263 | /* | |
264 | * The lockdep classes are in a hash-table as well, for fast lookup: | |
265 | */ | |
266 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) | |
267 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) | |
4b32d0a4 | 268 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
fbb9ce95 IM |
269 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
270 | ||
271 | static struct list_head classhash_table[CLASSHASH_SIZE]; | |
272 | ||
fbb9ce95 IM |
273 | /* |
274 | * We put the lock dependency chains into a hash-table as well, to cache | |
275 | * their existence: | |
276 | */ | |
277 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) | |
278 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) | |
4b32d0a4 | 279 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
fbb9ce95 IM |
280 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
281 | ||
282 | static struct list_head chainhash_table[CHAINHASH_SIZE]; | |
283 | ||
284 | /* | |
285 | * The hash key of the lock dependency chains is a hash itself too: | |
286 | * it's a hash of all locks taken up to that lock, including that lock. | |
287 | * It's a 64-bit hash, because it's important for the keys to be | |
288 | * unique. | |
289 | */ | |
290 | #define iterate_chain_key(key1, key2) \ | |
03cbc358 IM |
291 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
292 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ | |
fbb9ce95 IM |
293 | (key2)) |
294 | ||
1d09daa5 | 295 | void lockdep_off(void) |
fbb9ce95 IM |
296 | { |
297 | current->lockdep_recursion++; | |
298 | } | |
fbb9ce95 IM |
299 | EXPORT_SYMBOL(lockdep_off); |
300 | ||
1d09daa5 | 301 | void lockdep_on(void) |
fbb9ce95 IM |
302 | { |
303 | current->lockdep_recursion--; | |
304 | } | |
fbb9ce95 IM |
305 | EXPORT_SYMBOL(lockdep_on); |
306 | ||
fbb9ce95 IM |
307 | /* |
308 | * Debugging switches: | |
309 | */ | |
310 | ||
311 | #define VERBOSE 0 | |
33e94e96 | 312 | #define VERY_VERBOSE 0 |
fbb9ce95 IM |
313 | |
314 | #if VERBOSE | |
315 | # define HARDIRQ_VERBOSE 1 | |
316 | # define SOFTIRQ_VERBOSE 1 | |
cf40bd16 | 317 | # define RECLAIM_VERBOSE 1 |
fbb9ce95 IM |
318 | #else |
319 | # define HARDIRQ_VERBOSE 0 | |
320 | # define SOFTIRQ_VERBOSE 0 | |
cf40bd16 | 321 | # define RECLAIM_VERBOSE 0 |
fbb9ce95 IM |
322 | #endif |
323 | ||
cf40bd16 | 324 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
fbb9ce95 IM |
325 | /* |
326 | * Quick filtering for interesting events: | |
327 | */ | |
328 | static int class_filter(struct lock_class *class) | |
329 | { | |
f9829cce AK |
330 | #if 0 |
331 | /* Example */ | |
fbb9ce95 | 332 | if (class->name_version == 1 && |
f9829cce | 333 | !strcmp(class->name, "lockname")) |
fbb9ce95 IM |
334 | return 1; |
335 | if (class->name_version == 1 && | |
f9829cce | 336 | !strcmp(class->name, "&struct->lockfield")) |
fbb9ce95 | 337 | return 1; |
f9829cce | 338 | #endif |
a6640897 IM |
339 | /* Filter everything else. 1 would be to allow everything else */ |
340 | return 0; | |
fbb9ce95 IM |
341 | } |
342 | #endif | |
343 | ||
344 | static int verbose(struct lock_class *class) | |
345 | { | |
346 | #if VERBOSE | |
347 | return class_filter(class); | |
348 | #endif | |
349 | return 0; | |
350 | } | |
351 | ||
fbb9ce95 IM |
352 | /* |
353 | * Stack-trace: tightly packed array of stack backtrace | |
74c383f1 | 354 | * addresses. Protected by the graph_lock. |
fbb9ce95 IM |
355 | */ |
356 | unsigned long nr_stack_trace_entries; | |
357 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; | |
358 | ||
359 | static int save_trace(struct stack_trace *trace) | |
360 | { | |
361 | trace->nr_entries = 0; | |
362 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; | |
363 | trace->entries = stack_trace + nr_stack_trace_entries; | |
364 | ||
5a1b3999 | 365 | trace->skip = 3; |
5a1b3999 | 366 | |
ab1b6f03 | 367 | save_stack_trace(trace); |
fbb9ce95 IM |
368 | |
369 | trace->max_entries = trace->nr_entries; | |
370 | ||
371 | nr_stack_trace_entries += trace->nr_entries; | |
fbb9ce95 IM |
372 | |
373 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { | |
74c383f1 IM |
374 | if (!debug_locks_off_graph_unlock()) |
375 | return 0; | |
376 | ||
377 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); | |
378 | printk("turning off the locking correctness validator.\n"); | |
379 | dump_stack(); | |
380 | ||
fbb9ce95 IM |
381 | return 0; |
382 | } | |
383 | ||
384 | return 1; | |
385 | } | |
386 | ||
387 | unsigned int nr_hardirq_chains; | |
388 | unsigned int nr_softirq_chains; | |
389 | unsigned int nr_process_chains; | |
390 | unsigned int max_lockdep_depth; | |
391 | unsigned int max_recursion_depth; | |
392 | ||
419ca3f1 DM |
393 | static unsigned int lockdep_dependency_gen_id; |
394 | ||
395 | static bool lockdep_dependency_visit(struct lock_class *source, | |
396 | unsigned int depth) | |
397 | { | |
398 | if (!depth) | |
399 | lockdep_dependency_gen_id++; | |
400 | if (source->dep_gen_id == lockdep_dependency_gen_id) | |
401 | return true; | |
402 | source->dep_gen_id = lockdep_dependency_gen_id; | |
403 | return false; | |
404 | } | |
405 | ||
fbb9ce95 IM |
406 | #ifdef CONFIG_DEBUG_LOCKDEP |
407 | /* | |
408 | * We cannot printk in early bootup code. Not even early_printk() | |
409 | * might work. So we mark any initialization errors and printk | |
410 | * about it later on, in lockdep_info(). | |
411 | */ | |
412 | static int lockdep_init_error; | |
c71063c9 JB |
413 | static unsigned long lockdep_init_trace_data[20]; |
414 | static struct stack_trace lockdep_init_trace = { | |
415 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), | |
416 | .entries = lockdep_init_trace_data, | |
417 | }; | |
fbb9ce95 IM |
418 | |
419 | /* | |
420 | * Various lockdep statistics: | |
421 | */ | |
422 | atomic_t chain_lookup_hits; | |
423 | atomic_t chain_lookup_misses; | |
424 | atomic_t hardirqs_on_events; | |
425 | atomic_t hardirqs_off_events; | |
426 | atomic_t redundant_hardirqs_on; | |
427 | atomic_t redundant_hardirqs_off; | |
428 | atomic_t softirqs_on_events; | |
429 | atomic_t softirqs_off_events; | |
430 | atomic_t redundant_softirqs_on; | |
431 | atomic_t redundant_softirqs_off; | |
432 | atomic_t nr_unused_locks; | |
433 | atomic_t nr_cyclic_checks; | |
434 | atomic_t nr_cyclic_check_recursions; | |
435 | atomic_t nr_find_usage_forwards_checks; | |
436 | atomic_t nr_find_usage_forwards_recursions; | |
437 | atomic_t nr_find_usage_backwards_checks; | |
438 | atomic_t nr_find_usage_backwards_recursions; | |
fbb9ce95 IM |
439 | #endif |
440 | ||
441 | /* | |
442 | * Locking printouts: | |
443 | */ | |
444 | ||
fabe9c42 | 445 | #define __USAGE(__STATE) \ |
b4b136f4 PZ |
446 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
447 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ | |
448 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ | |
449 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", | |
fabe9c42 | 450 | |
fbb9ce95 IM |
451 | static const char *usage_str[] = |
452 | { | |
fabe9c42 PZ |
453 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
454 | #include "lockdep_states.h" | |
455 | #undef LOCKDEP_STATE | |
456 | [LOCK_USED] = "INITIAL USE", | |
fbb9ce95 IM |
457 | }; |
458 | ||
459 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) | |
460 | { | |
ffb45122 | 461 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
fbb9ce95 IM |
462 | } |
463 | ||
3ff176ca | 464 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
fbb9ce95 | 465 | { |
3ff176ca PZ |
466 | return 1UL << bit; |
467 | } | |
fbb9ce95 | 468 | |
3ff176ca PZ |
469 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
470 | { | |
471 | char c = '.'; | |
472 | ||
473 | if (class->usage_mask & lock_flag(bit + 2)) | |
474 | c = '+'; | |
475 | if (class->usage_mask & lock_flag(bit)) { | |
476 | c = '-'; | |
477 | if (class->usage_mask & lock_flag(bit + 2)) | |
478 | c = '?'; | |
fbb9ce95 IM |
479 | } |
480 | ||
3ff176ca PZ |
481 | return c; |
482 | } | |
cf40bd16 | 483 | |
f510b233 | 484 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
3ff176ca | 485 | { |
f510b233 | 486 | int i = 0; |
cf40bd16 | 487 | |
f510b233 PZ |
488 | #define LOCKDEP_STATE(__STATE) \ |
489 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ | |
490 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); | |
491 | #include "lockdep_states.h" | |
492 | #undef LOCKDEP_STATE | |
493 | ||
494 | usage[i] = '\0'; | |
fbb9ce95 IM |
495 | } |
496 | ||
497 | static void print_lock_name(struct lock_class *class) | |
498 | { | |
f510b233 | 499 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
fbb9ce95 IM |
500 | const char *name; |
501 | ||
f510b233 | 502 | get_usage_chars(class, usage); |
fbb9ce95 IM |
503 | |
504 | name = class->name; | |
505 | if (!name) { | |
506 | name = __get_key_name(class->key, str); | |
507 | printk(" (%s", name); | |
508 | } else { | |
509 | printk(" (%s", name); | |
510 | if (class->name_version > 1) | |
511 | printk("#%d", class->name_version); | |
512 | if (class->subclass) | |
513 | printk("/%d", class->subclass); | |
514 | } | |
f510b233 | 515 | printk("){%s}", usage); |
fbb9ce95 IM |
516 | } |
517 | ||
518 | static void print_lockdep_cache(struct lockdep_map *lock) | |
519 | { | |
520 | const char *name; | |
9281acea | 521 | char str[KSYM_NAME_LEN]; |
fbb9ce95 IM |
522 | |
523 | name = lock->name; | |
524 | if (!name) | |
525 | name = __get_key_name(lock->key->subkeys, str); | |
526 | ||
527 | printk("%s", name); | |
528 | } | |
529 | ||
530 | static void print_lock(struct held_lock *hlock) | |
531 | { | |
f82b217e | 532 | print_lock_name(hlock_class(hlock)); |
fbb9ce95 IM |
533 | printk(", at: "); |
534 | print_ip_sym(hlock->acquire_ip); | |
535 | } | |
536 | ||
537 | static void lockdep_print_held_locks(struct task_struct *curr) | |
538 | { | |
539 | int i, depth = curr->lockdep_depth; | |
540 | ||
541 | if (!depth) { | |
ba25f9dc | 542 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
543 | return; |
544 | } | |
545 | printk("%d lock%s held by %s/%d:\n", | |
ba25f9dc | 546 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
547 | |
548 | for (i = 0; i < depth; i++) { | |
549 | printk(" #%d: ", i); | |
550 | print_lock(curr->held_locks + i); | |
551 | } | |
552 | } | |
fbb9ce95 IM |
553 | |
554 | static void print_lock_class_header(struct lock_class *class, int depth) | |
555 | { | |
556 | int bit; | |
557 | ||
f9829cce | 558 | printk("%*s->", depth, ""); |
fbb9ce95 IM |
559 | print_lock_name(class); |
560 | printk(" ops: %lu", class->ops); | |
561 | printk(" {\n"); | |
562 | ||
563 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { | |
564 | if (class->usage_mask & (1 << bit)) { | |
565 | int len = depth; | |
566 | ||
f9829cce | 567 | len += printk("%*s %s", depth, "", usage_str[bit]); |
fbb9ce95 IM |
568 | len += printk(" at:\n"); |
569 | print_stack_trace(class->usage_traces + bit, len); | |
570 | } | |
571 | } | |
f9829cce | 572 | printk("%*s }\n", depth, ""); |
fbb9ce95 | 573 | |
f9829cce | 574 | printk("%*s ... key at: ",depth,""); |
fbb9ce95 IM |
575 | print_ip_sym((unsigned long)class->key); |
576 | } | |
577 | ||
578 | /* | |
579 | * printk all lock dependencies starting at <entry>: | |
580 | */ | |
7807fafa IM |
581 | static void __used |
582 | print_lock_dependencies(struct lock_class *class, int depth) | |
fbb9ce95 IM |
583 | { |
584 | struct lock_list *entry; | |
585 | ||
419ca3f1 DM |
586 | if (lockdep_dependency_visit(class, depth)) |
587 | return; | |
588 | ||
fbb9ce95 IM |
589 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
590 | return; | |
591 | ||
592 | print_lock_class_header(class, depth); | |
593 | ||
594 | list_for_each_entry(entry, &class->locks_after, entry) { | |
b23984d0 JP |
595 | if (DEBUG_LOCKS_WARN_ON(!entry->class)) |
596 | return; | |
597 | ||
fbb9ce95 IM |
598 | print_lock_dependencies(entry->class, depth + 1); |
599 | ||
f9829cce | 600 | printk("%*s ... acquired at:\n",depth,""); |
fbb9ce95 IM |
601 | print_stack_trace(&entry->trace, 2); |
602 | printk("\n"); | |
603 | } | |
604 | } | |
605 | ||
8e18257d PZ |
606 | static void print_kernel_version(void) |
607 | { | |
608 | printk("%s %.*s\n", init_utsname()->release, | |
609 | (int)strcspn(init_utsname()->version, " "), | |
610 | init_utsname()->version); | |
611 | } | |
612 | ||
613 | static int very_verbose(struct lock_class *class) | |
614 | { | |
615 | #if VERY_VERBOSE | |
616 | return class_filter(class); | |
617 | #endif | |
618 | return 0; | |
619 | } | |
620 | ||
fbb9ce95 | 621 | /* |
8e18257d | 622 | * Is this the address of a static object: |
fbb9ce95 | 623 | */ |
8e18257d | 624 | static int static_obj(void *obj) |
fbb9ce95 | 625 | { |
8e18257d PZ |
626 | unsigned long start = (unsigned long) &_stext, |
627 | end = (unsigned long) &_end, | |
628 | addr = (unsigned long) obj; | |
629 | #ifdef CONFIG_SMP | |
630 | int i; | |
631 | #endif | |
632 | ||
fbb9ce95 | 633 | /* |
8e18257d | 634 | * static variable? |
fbb9ce95 | 635 | */ |
8e18257d PZ |
636 | if ((addr >= start) && (addr < end)) |
637 | return 1; | |
fbb9ce95 | 638 | |
8e18257d | 639 | #ifdef CONFIG_SMP |
fbb9ce95 | 640 | /* |
8e18257d | 641 | * percpu var? |
fbb9ce95 | 642 | */ |
8e18257d PZ |
643 | for_each_possible_cpu(i) { |
644 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); | |
645 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM | |
646 | + per_cpu_offset(i); | |
fbb9ce95 | 647 | |
8e18257d PZ |
648 | if ((addr >= start) && (addr < end)) |
649 | return 1; | |
650 | } | |
ca58abcb | 651 | #endif |
fbb9ce95 | 652 | |
8e18257d PZ |
653 | /* |
654 | * module var? | |
655 | */ | |
656 | return is_module_address(addr); | |
99de055a DJ |
657 | } |
658 | ||
fbb9ce95 | 659 | /* |
8e18257d PZ |
660 | * To make lock name printouts unique, we calculate a unique |
661 | * class->name_version generation counter: | |
fbb9ce95 | 662 | */ |
8e18257d | 663 | static int count_matching_names(struct lock_class *new_class) |
fbb9ce95 | 664 | { |
8e18257d PZ |
665 | struct lock_class *class; |
666 | int count = 0; | |
fbb9ce95 | 667 | |
8e18257d | 668 | if (!new_class->name) |
fbb9ce95 IM |
669 | return 0; |
670 | ||
8e18257d PZ |
671 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
672 | if (new_class->key - new_class->subclass == class->key) | |
673 | return class->name_version; | |
674 | if (class->name && !strcmp(class->name, new_class->name)) | |
675 | count = max(count, class->name_version); | |
676 | } | |
fbb9ce95 | 677 | |
8e18257d | 678 | return count + 1; |
fbb9ce95 IM |
679 | } |
680 | ||
8e18257d PZ |
681 | /* |
682 | * Register a lock's class in the hash-table, if the class is not present | |
683 | * yet. Otherwise we look it up. We cache the result in the lock object | |
684 | * itself, so actual lookup of the hash should be once per lock object. | |
685 | */ | |
686 | static inline struct lock_class * | |
687 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) | |
fbb9ce95 | 688 | { |
8e18257d PZ |
689 | struct lockdep_subclass_key *key; |
690 | struct list_head *hash_head; | |
691 | struct lock_class *class; | |
fbb9ce95 | 692 | |
8e18257d PZ |
693 | #ifdef CONFIG_DEBUG_LOCKDEP |
694 | /* | |
695 | * If the architecture calls into lockdep before initializing | |
696 | * the hashes then we'll warn about it later. (we cannot printk | |
697 | * right now) | |
698 | */ | |
699 | if (unlikely(!lockdep_initialized)) { | |
700 | lockdep_init(); | |
701 | lockdep_init_error = 1; | |
c71063c9 | 702 | save_stack_trace(&lockdep_init_trace); |
8e18257d PZ |
703 | } |
704 | #endif | |
fbb9ce95 | 705 | |
8e18257d PZ |
706 | /* |
707 | * Static locks do not have their class-keys yet - for them the key | |
708 | * is the lock object itself: | |
709 | */ | |
710 | if (unlikely(!lock->key)) | |
711 | lock->key = (void *)lock; | |
fbb9ce95 | 712 | |
8e18257d PZ |
713 | /* |
714 | * NOTE: the class-key must be unique. For dynamic locks, a static | |
715 | * lock_class_key variable is passed in through the mutex_init() | |
716 | * (or spin_lock_init()) call - which acts as the key. For static | |
717 | * locks we use the lock object itself as the key. | |
718 | */ | |
4b32d0a4 PZ |
719 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
720 | sizeof(struct lockdep_map)); | |
fbb9ce95 | 721 | |
8e18257d | 722 | key = lock->key->subkeys + subclass; |
ca268c69 | 723 | |
8e18257d | 724 | hash_head = classhashentry(key); |
74c383f1 | 725 | |
8e18257d PZ |
726 | /* |
727 | * We can walk the hash lockfree, because the hash only | |
728 | * grows, and we are careful when adding entries to the end: | |
729 | */ | |
4b32d0a4 PZ |
730 | list_for_each_entry(class, hash_head, hash_entry) { |
731 | if (class->key == key) { | |
732 | WARN_ON_ONCE(class->name != lock->name); | |
8e18257d | 733 | return class; |
4b32d0a4 PZ |
734 | } |
735 | } | |
fbb9ce95 | 736 | |
8e18257d | 737 | return NULL; |
fbb9ce95 IM |
738 | } |
739 | ||
740 | /* | |
8e18257d PZ |
741 | * Register a lock's class in the hash-table, if the class is not present |
742 | * yet. Otherwise we look it up. We cache the result in the lock object | |
743 | * itself, so actual lookup of the hash should be once per lock object. | |
fbb9ce95 | 744 | */ |
8e18257d PZ |
745 | static inline struct lock_class * |
746 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) | |
fbb9ce95 | 747 | { |
8e18257d PZ |
748 | struct lockdep_subclass_key *key; |
749 | struct list_head *hash_head; | |
750 | struct lock_class *class; | |
751 | unsigned long flags; | |
752 | ||
753 | class = look_up_lock_class(lock, subclass); | |
754 | if (likely(class)) | |
755 | return class; | |
756 | ||
757 | /* | |
758 | * Debug-check: all keys must be persistent! | |
759 | */ | |
760 | if (!static_obj(lock->key)) { | |
761 | debug_locks_off(); | |
762 | printk("INFO: trying to register non-static key.\n"); | |
763 | printk("the code is fine but needs lockdep annotation.\n"); | |
764 | printk("turning off the locking correctness validator.\n"); | |
765 | dump_stack(); | |
766 | ||
767 | return NULL; | |
768 | } | |
769 | ||
770 | key = lock->key->subkeys + subclass; | |
771 | hash_head = classhashentry(key); | |
772 | ||
773 | raw_local_irq_save(flags); | |
774 | if (!graph_lock()) { | |
775 | raw_local_irq_restore(flags); | |
776 | return NULL; | |
777 | } | |
778 | /* | |
779 | * We have to do the hash-walk again, to avoid races | |
780 | * with another CPU: | |
781 | */ | |
782 | list_for_each_entry(class, hash_head, hash_entry) | |
783 | if (class->key == key) | |
784 | goto out_unlock_set; | |
785 | /* | |
786 | * Allocate a new key from the static array, and add it to | |
787 | * the hash: | |
788 | */ | |
789 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { | |
790 | if (!debug_locks_off_graph_unlock()) { | |
791 | raw_local_irq_restore(flags); | |
792 | return NULL; | |
793 | } | |
794 | raw_local_irq_restore(flags); | |
795 | ||
796 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); | |
797 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 798 | dump_stack(); |
8e18257d PZ |
799 | return NULL; |
800 | } | |
801 | class = lock_classes + nr_lock_classes++; | |
802 | debug_atomic_inc(&nr_unused_locks); | |
803 | class->key = key; | |
804 | class->name = lock->name; | |
805 | class->subclass = subclass; | |
806 | INIT_LIST_HEAD(&class->lock_entry); | |
807 | INIT_LIST_HEAD(&class->locks_before); | |
808 | INIT_LIST_HEAD(&class->locks_after); | |
809 | class->name_version = count_matching_names(class); | |
810 | /* | |
811 | * We use RCU's safe list-add method to make | |
812 | * parallel walking of the hash-list safe: | |
813 | */ | |
814 | list_add_tail_rcu(&class->hash_entry, hash_head); | |
1481197b DF |
815 | /* |
816 | * Add it to the global list of classes: | |
817 | */ | |
818 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); | |
8e18257d PZ |
819 | |
820 | if (verbose(class)) { | |
821 | graph_unlock(); | |
822 | raw_local_irq_restore(flags); | |
823 | ||
824 | printk("\nnew class %p: %s", class->key, class->name); | |
825 | if (class->name_version > 1) | |
826 | printk("#%d", class->name_version); | |
827 | printk("\n"); | |
828 | dump_stack(); | |
829 | ||
830 | raw_local_irq_save(flags); | |
831 | if (!graph_lock()) { | |
832 | raw_local_irq_restore(flags); | |
833 | return NULL; | |
834 | } | |
835 | } | |
836 | out_unlock_set: | |
837 | graph_unlock(); | |
838 | raw_local_irq_restore(flags); | |
839 | ||
840 | if (!subclass || force) | |
841 | lock->class_cache = class; | |
842 | ||
843 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) | |
844 | return NULL; | |
845 | ||
846 | return class; | |
847 | } | |
848 | ||
849 | #ifdef CONFIG_PROVE_LOCKING | |
850 | /* | |
851 | * Allocate a lockdep entry. (assumes the graph_lock held, returns | |
852 | * with NULL on failure) | |
853 | */ | |
854 | static struct lock_list *alloc_list_entry(void) | |
855 | { | |
856 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { | |
857 | if (!debug_locks_off_graph_unlock()) | |
858 | return NULL; | |
859 | ||
860 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); | |
861 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 862 | dump_stack(); |
8e18257d PZ |
863 | return NULL; |
864 | } | |
865 | return list_entries + nr_list_entries++; | |
866 | } | |
867 | ||
868 | /* | |
869 | * Add a new dependency to the head of the list: | |
870 | */ | |
871 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, | |
872 | struct list_head *head, unsigned long ip, int distance) | |
873 | { | |
874 | struct lock_list *entry; | |
875 | /* | |
876 | * Lock not present yet - get a new dependency struct and | |
877 | * add it to the list: | |
878 | */ | |
879 | entry = alloc_list_entry(); | |
880 | if (!entry) | |
881 | return 0; | |
882 | ||
8e18257d PZ |
883 | if (!save_trace(&entry->trace)) |
884 | return 0; | |
885 | ||
74870172 ZY |
886 | entry->class = this; |
887 | entry->distance = distance; | |
8e18257d PZ |
888 | /* |
889 | * Since we never remove from the dependency list, the list can | |
890 | * be walked lockless by other CPUs, it's only allocation | |
891 | * that must be protected by the spinlock. But this also means | |
892 | * we must make new entries visible only once writes to the | |
893 | * entry become visible - hence the RCU op: | |
894 | */ | |
895 | list_add_tail_rcu(&entry->entry, head); | |
896 | ||
897 | return 1; | |
898 | } | |
899 | ||
d588e461 | 900 | unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)]; |
c94aa5ca | 901 | static struct circular_queue lock_cq; |
d588e461 | 902 | |
c94aa5ca ML |
903 | static int __search_shortest_path(struct lock_list *source_entry, |
904 | struct lock_class *target, | |
905 | struct lock_list **target_entry, | |
906 | int forward) | |
907 | { | |
908 | struct lock_list *entry; | |
d588e461 | 909 | struct list_head *head; |
c94aa5ca ML |
910 | struct circular_queue *cq = &lock_cq; |
911 | int ret = 1; | |
912 | ||
c94aa5ca ML |
913 | if (source_entry->class == target) { |
914 | *target_entry = source_entry; | |
915 | ret = 0; | |
916 | goto exit; | |
917 | } | |
918 | ||
d588e461 ML |
919 | if (forward) |
920 | head = &source_entry->class->locks_after; | |
921 | else | |
922 | head = &source_entry->class->locks_before; | |
923 | ||
924 | if (list_empty(head)) | |
925 | goto exit; | |
926 | ||
927 | __cq_init(cq); | |
c94aa5ca ML |
928 | __cq_enqueue(cq, (unsigned long)source_entry); |
929 | ||
930 | while (!__cq_empty(cq)) { | |
931 | struct lock_list *lock; | |
c94aa5ca ML |
932 | |
933 | __cq_dequeue(cq, (unsigned long *)&lock); | |
934 | ||
935 | if (!lock->class) { | |
936 | ret = -2; | |
937 | goto exit; | |
938 | } | |
939 | ||
940 | if (forward) | |
941 | head = &lock->class->locks_after; | |
942 | else | |
943 | head = &lock->class->locks_before; | |
944 | ||
945 | list_for_each_entry(entry, head, entry) { | |
946 | if (!lock_accessed(entry)) { | |
947 | mark_lock_accessed(entry, lock); | |
948 | if (entry->class == target) { | |
949 | *target_entry = entry; | |
950 | ret = 0; | |
951 | goto exit; | |
952 | } | |
953 | ||
954 | if (__cq_enqueue(cq, (unsigned long)entry)) { | |
955 | ret = -1; | |
956 | goto exit; | |
957 | } | |
958 | } | |
959 | } | |
960 | } | |
961 | exit: | |
962 | return ret; | |
963 | } | |
964 | ||
965 | static inline int __search_forward_shortest_path(struct lock_list *src_entry, | |
966 | struct lock_class *target, | |
967 | struct lock_list **target_entry) | |
968 | { | |
969 | return __search_shortest_path(src_entry, target, target_entry, 1); | |
970 | ||
971 | } | |
972 | ||
973 | static inline int __search_backward_shortest_path(struct lock_list *src_entry, | |
974 | struct lock_class *target, | |
975 | struct lock_list **target_entry) | |
976 | { | |
977 | return __search_shortest_path(src_entry, target, target_entry, 0); | |
978 | ||
979 | } | |
980 | ||
8e18257d PZ |
981 | /* |
982 | * Recursive, forwards-direction lock-dependency checking, used for | |
983 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe | |
984 | * checking. | |
985 | * | |
986 | * (to keep the stackframe of the recursive functions small we | |
987 | * use these global variables, and we also mark various helper | |
988 | * functions as noinline.) | |
989 | */ | |
990 | static struct held_lock *check_source, *check_target; | |
991 | ||
992 | /* | |
993 | * Print a dependency chain entry (this is only done when a deadlock | |
994 | * has been detected): | |
995 | */ | |
996 | static noinline int | |
997 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) | |
998 | { | |
999 | if (debug_locks_silent) | |
1000 | return 0; | |
1001 | printk("\n-> #%u", depth); | |
1002 | print_lock_name(target->class); | |
1003 | printk(":\n"); | |
1004 | print_stack_trace(&target->trace, 6); | |
1005 | ||
1006 | return 0; | |
1007 | } | |
1008 | ||
1009 | /* | |
1010 | * When a circular dependency is detected, print the | |
1011 | * header first: | |
1012 | */ | |
1013 | static noinline int | |
1014 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) | |
1015 | { | |
1016 | struct task_struct *curr = current; | |
1017 | ||
c94aa5ca | 1018 | if (debug_locks_silent) |
8e18257d PZ |
1019 | return 0; |
1020 | ||
1021 | printk("\n=======================================================\n"); | |
1022 | printk( "[ INFO: possible circular locking dependency detected ]\n"); | |
1023 | print_kernel_version(); | |
1024 | printk( "-------------------------------------------------------\n"); | |
1025 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1026 | curr->comm, task_pid_nr(curr)); |
8e18257d PZ |
1027 | print_lock(check_source); |
1028 | printk("\nbut task is already holding lock:\n"); | |
1029 | print_lock(check_target); | |
1030 | printk("\nwhich lock already depends on the new lock.\n\n"); | |
1031 | printk("\nthe existing dependency chain (in reverse order) is:\n"); | |
1032 | ||
1033 | print_circular_bug_entry(entry, depth); | |
1034 | ||
1035 | return 0; | |
1036 | } | |
1037 | ||
c94aa5ca | 1038 | static noinline int print_circular_bug(void) |
8e18257d PZ |
1039 | { |
1040 | struct task_struct *curr = current; | |
1041 | struct lock_list this; | |
c94aa5ca ML |
1042 | struct lock_list *target; |
1043 | struct lock_list *parent; | |
1044 | int result; | |
1045 | unsigned long depth; | |
8e18257d | 1046 | |
c94aa5ca | 1047 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
8e18257d PZ |
1048 | return 0; |
1049 | ||
f82b217e | 1050 | this.class = hlock_class(check_source); |
d588e461 | 1051 | this.parent = NULL; |
8e18257d PZ |
1052 | if (!save_trace(&this.trace)) |
1053 | return 0; | |
1054 | ||
c94aa5ca ML |
1055 | result = __search_forward_shortest_path(&this, |
1056 | hlock_class(check_target), | |
1057 | &target); | |
1058 | if (result) { | |
1059 | printk("\n%s:search shortest path failed:%d\n", __func__, | |
1060 | result); | |
1061 | return 0; | |
1062 | } | |
1063 | ||
1064 | depth = get_lock_depth(target); | |
1065 | ||
1066 | print_circular_bug_header(target, depth); | |
1067 | ||
1068 | parent = get_lock_parent(target); | |
1069 | ||
1070 | while (parent) { | |
1071 | print_circular_bug_entry(parent, --depth); | |
1072 | parent = get_lock_parent(parent); | |
1073 | } | |
8e18257d PZ |
1074 | |
1075 | printk("\nother info that might help us debug this:\n\n"); | |
1076 | lockdep_print_held_locks(curr); | |
1077 | ||
1078 | printk("\nstack backtrace:\n"); | |
1079 | dump_stack(); | |
1080 | ||
1081 | return 0; | |
1082 | } | |
1083 | ||
1084 | #define RECURSION_LIMIT 40 | |
1085 | ||
1086 | static int noinline print_infinite_recursion_bug(void) | |
1087 | { | |
1088 | if (!debug_locks_off_graph_unlock()) | |
1089 | return 0; | |
1090 | ||
1091 | WARN_ON(1); | |
1092 | ||
1093 | return 0; | |
1094 | } | |
1095 | ||
419ca3f1 DM |
1096 | unsigned long __lockdep_count_forward_deps(struct lock_class *class, |
1097 | unsigned int depth) | |
1098 | { | |
1099 | struct lock_list *entry; | |
1100 | unsigned long ret = 1; | |
1101 | ||
1102 | if (lockdep_dependency_visit(class, depth)) | |
1103 | return 0; | |
1104 | ||
1105 | /* | |
1106 | * Recurse this class's dependency list: | |
1107 | */ | |
1108 | list_for_each_entry(entry, &class->locks_after, entry) | |
1109 | ret += __lockdep_count_forward_deps(entry->class, depth + 1); | |
1110 | ||
1111 | return ret; | |
1112 | } | |
1113 | ||
1114 | unsigned long lockdep_count_forward_deps(struct lock_class *class) | |
1115 | { | |
1116 | unsigned long ret, flags; | |
1117 | ||
1118 | local_irq_save(flags); | |
1119 | __raw_spin_lock(&lockdep_lock); | |
1120 | ret = __lockdep_count_forward_deps(class, 0); | |
1121 | __raw_spin_unlock(&lockdep_lock); | |
1122 | local_irq_restore(flags); | |
1123 | ||
1124 | return ret; | |
1125 | } | |
1126 | ||
1127 | unsigned long __lockdep_count_backward_deps(struct lock_class *class, | |
1128 | unsigned int depth) | |
1129 | { | |
1130 | struct lock_list *entry; | |
1131 | unsigned long ret = 1; | |
1132 | ||
1133 | if (lockdep_dependency_visit(class, depth)) | |
1134 | return 0; | |
1135 | /* | |
1136 | * Recurse this class's dependency list: | |
1137 | */ | |
1138 | list_for_each_entry(entry, &class->locks_before, entry) | |
1139 | ret += __lockdep_count_backward_deps(entry->class, depth + 1); | |
1140 | ||
1141 | return ret; | |
1142 | } | |
1143 | ||
1144 | unsigned long lockdep_count_backward_deps(struct lock_class *class) | |
1145 | { | |
1146 | unsigned long ret, flags; | |
1147 | ||
1148 | local_irq_save(flags); | |
1149 | __raw_spin_lock(&lockdep_lock); | |
1150 | ret = __lockdep_count_backward_deps(class, 0); | |
1151 | __raw_spin_unlock(&lockdep_lock); | |
1152 | local_irq_restore(flags); | |
1153 | ||
1154 | return ret; | |
1155 | } | |
1156 | ||
8e18257d PZ |
1157 | /* |
1158 | * Prove that the dependency graph starting at <entry> can not | |
1159 | * lead to <target>. Print an error and return 0 if it does. | |
1160 | */ | |
1161 | static noinline int | |
1162 | check_noncircular(struct lock_class *source, unsigned int depth) | |
1163 | { | |
1164 | struct lock_list *entry; | |
1165 | ||
419ca3f1 DM |
1166 | if (lockdep_dependency_visit(source, depth)) |
1167 | return 1; | |
1168 | ||
8e18257d PZ |
1169 | debug_atomic_inc(&nr_cyclic_check_recursions); |
1170 | if (depth > max_recursion_depth) | |
fbb9ce95 | 1171 | max_recursion_depth = depth; |
ca268c69 | 1172 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1173 | return print_infinite_recursion_bug(); |
1174 | /* | |
1175 | * Check this lock's dependency list: | |
1176 | */ | |
1177 | list_for_each_entry(entry, &source->locks_after, entry) { | |
f82b217e | 1178 | if (entry->class == hlock_class(check_target)) |
c94aa5ca | 1179 | return 2; |
fbb9ce95 | 1180 | debug_atomic_inc(&nr_cyclic_checks); |
c94aa5ca ML |
1181 | if (check_noncircular(entry->class, depth+1) == 2) |
1182 | return 2; | |
fbb9ce95 IM |
1183 | } |
1184 | return 1; | |
1185 | } | |
1186 | ||
c94aa5ca | 1187 | |
81d68a96 | 1188 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1189 | /* |
1190 | * Forwards and backwards subgraph searching, for the purposes of | |
1191 | * proving that two subgraphs can be connected by a new dependency | |
1192 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. | |
1193 | */ | |
1194 | static enum lock_usage_bit find_usage_bit; | |
1195 | static struct lock_class *forwards_match, *backwards_match; | |
1196 | ||
1197 | /* | |
1198 | * Find a node in the forwards-direction dependency sub-graph starting | |
1199 | * at <source> that matches <find_usage_bit>. | |
1200 | * | |
1201 | * Return 2 if such a node exists in the subgraph, and put that node | |
1202 | * into <forwards_match>. | |
1203 | * | |
1204 | * Return 1 otherwise and keep <forwards_match> unchanged. | |
1205 | * Return 0 on error. | |
1206 | */ | |
1207 | static noinline int | |
1208 | find_usage_forwards(struct lock_class *source, unsigned int depth) | |
1209 | { | |
1210 | struct lock_list *entry; | |
1211 | int ret; | |
1212 | ||
419ca3f1 DM |
1213 | if (lockdep_dependency_visit(source, depth)) |
1214 | return 1; | |
1215 | ||
fbb9ce95 IM |
1216 | if (depth > max_recursion_depth) |
1217 | max_recursion_depth = depth; | |
ca268c69 | 1218 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1219 | return print_infinite_recursion_bug(); |
1220 | ||
1221 | debug_atomic_inc(&nr_find_usage_forwards_checks); | |
1222 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1223 | forwards_match = source; | |
1224 | return 2; | |
1225 | } | |
1226 | ||
1227 | /* | |
1228 | * Check this lock's dependency list: | |
1229 | */ | |
1230 | list_for_each_entry(entry, &source->locks_after, entry) { | |
1231 | debug_atomic_inc(&nr_find_usage_forwards_recursions); | |
1232 | ret = find_usage_forwards(entry->class, depth+1); | |
1233 | if (ret == 2 || ret == 0) | |
1234 | return ret; | |
1235 | } | |
1236 | return 1; | |
1237 | } | |
1238 | ||
1239 | /* | |
1240 | * Find a node in the backwards-direction dependency sub-graph starting | |
1241 | * at <source> that matches <find_usage_bit>. | |
1242 | * | |
1243 | * Return 2 if such a node exists in the subgraph, and put that node | |
1244 | * into <backwards_match>. | |
1245 | * | |
1246 | * Return 1 otherwise and keep <backwards_match> unchanged. | |
1247 | * Return 0 on error. | |
1248 | */ | |
1d09daa5 | 1249 | static noinline int |
fbb9ce95 IM |
1250 | find_usage_backwards(struct lock_class *source, unsigned int depth) |
1251 | { | |
1252 | struct lock_list *entry; | |
1253 | int ret; | |
1254 | ||
419ca3f1 DM |
1255 | if (lockdep_dependency_visit(source, depth)) |
1256 | return 1; | |
1257 | ||
381a2292 JP |
1258 | if (!__raw_spin_is_locked(&lockdep_lock)) |
1259 | return DEBUG_LOCKS_WARN_ON(1); | |
1260 | ||
fbb9ce95 IM |
1261 | if (depth > max_recursion_depth) |
1262 | max_recursion_depth = depth; | |
ca268c69 | 1263 | if (depth >= RECURSION_LIMIT) |
fbb9ce95 IM |
1264 | return print_infinite_recursion_bug(); |
1265 | ||
1266 | debug_atomic_inc(&nr_find_usage_backwards_checks); | |
1267 | if (source->usage_mask & (1 << find_usage_bit)) { | |
1268 | backwards_match = source; | |
1269 | return 2; | |
1270 | } | |
1271 | ||
f82b217e DJ |
1272 | if (!source && debug_locks_off_graph_unlock()) { |
1273 | WARN_ON(1); | |
1274 | return 0; | |
1275 | } | |
1276 | ||
fbb9ce95 IM |
1277 | /* |
1278 | * Check this lock's dependency list: | |
1279 | */ | |
1280 | list_for_each_entry(entry, &source->locks_before, entry) { | |
1281 | debug_atomic_inc(&nr_find_usage_backwards_recursions); | |
1282 | ret = find_usage_backwards(entry->class, depth+1); | |
1283 | if (ret == 2 || ret == 0) | |
1284 | return ret; | |
1285 | } | |
1286 | return 1; | |
1287 | } | |
1288 | ||
1289 | static int | |
1290 | print_bad_irq_dependency(struct task_struct *curr, | |
1291 | struct held_lock *prev, | |
1292 | struct held_lock *next, | |
1293 | enum lock_usage_bit bit1, | |
1294 | enum lock_usage_bit bit2, | |
1295 | const char *irqclass) | |
1296 | { | |
74c383f1 | 1297 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1298 | return 0; |
1299 | ||
1300 | printk("\n======================================================\n"); | |
1301 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", | |
1302 | irqclass, irqclass); | |
99de055a | 1303 | print_kernel_version(); |
fbb9ce95 IM |
1304 | printk( "------------------------------------------------------\n"); |
1305 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", | |
ba25f9dc | 1306 | curr->comm, task_pid_nr(curr), |
fbb9ce95 IM |
1307 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
1308 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, | |
1309 | curr->hardirqs_enabled, | |
1310 | curr->softirqs_enabled); | |
1311 | print_lock(next); | |
1312 | ||
1313 | printk("\nand this task is already holding:\n"); | |
1314 | print_lock(prev); | |
1315 | printk("which would create a new lock dependency:\n"); | |
f82b217e | 1316 | print_lock_name(hlock_class(prev)); |
fbb9ce95 | 1317 | printk(" ->"); |
f82b217e | 1318 | print_lock_name(hlock_class(next)); |
fbb9ce95 IM |
1319 | printk("\n"); |
1320 | ||
1321 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", | |
1322 | irqclass); | |
1323 | print_lock_name(backwards_match); | |
1324 | printk("\n... which became %s-irq-safe at:\n", irqclass); | |
1325 | ||
1326 | print_stack_trace(backwards_match->usage_traces + bit1, 1); | |
1327 | ||
1328 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); | |
1329 | print_lock_name(forwards_match); | |
1330 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); | |
1331 | printk("..."); | |
1332 | ||
1333 | print_stack_trace(forwards_match->usage_traces + bit2, 1); | |
1334 | ||
1335 | printk("\nother info that might help us debug this:\n\n"); | |
1336 | lockdep_print_held_locks(curr); | |
1337 | ||
1338 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); | |
1339 | print_lock_dependencies(backwards_match, 0); | |
1340 | ||
1341 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); | |
1342 | print_lock_dependencies(forwards_match, 0); | |
1343 | ||
1344 | printk("\nstack backtrace:\n"); | |
1345 | dump_stack(); | |
1346 | ||
1347 | return 0; | |
1348 | } | |
1349 | ||
1350 | static int | |
1351 | check_usage(struct task_struct *curr, struct held_lock *prev, | |
1352 | struct held_lock *next, enum lock_usage_bit bit_backwards, | |
1353 | enum lock_usage_bit bit_forwards, const char *irqclass) | |
1354 | { | |
1355 | int ret; | |
1356 | ||
1357 | find_usage_bit = bit_backwards; | |
1358 | /* fills in <backwards_match> */ | |
f82b217e | 1359 | ret = find_usage_backwards(hlock_class(prev), 0); |
fbb9ce95 IM |
1360 | if (!ret || ret == 1) |
1361 | return ret; | |
1362 | ||
1363 | find_usage_bit = bit_forwards; | |
f82b217e | 1364 | ret = find_usage_forwards(hlock_class(next), 0); |
fbb9ce95 IM |
1365 | if (!ret || ret == 1) |
1366 | return ret; | |
1367 | /* ret == 2 */ | |
1368 | return print_bad_irq_dependency(curr, prev, next, | |
1369 | bit_backwards, bit_forwards, irqclass); | |
1370 | } | |
1371 | ||
4f367d8a PZ |
1372 | static const char *state_names[] = { |
1373 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1374 | __stringify(__STATE), |
4f367d8a PZ |
1375 | #include "lockdep_states.h" |
1376 | #undef LOCKDEP_STATE | |
1377 | }; | |
1378 | ||
1379 | static const char *state_rnames[] = { | |
1380 | #define LOCKDEP_STATE(__STATE) \ | |
b4b136f4 | 1381 | __stringify(__STATE)"-READ", |
4f367d8a PZ |
1382 | #include "lockdep_states.h" |
1383 | #undef LOCKDEP_STATE | |
1384 | }; | |
1385 | ||
1386 | static inline const char *state_name(enum lock_usage_bit bit) | |
8e18257d | 1387 | { |
4f367d8a PZ |
1388 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
1389 | } | |
8e18257d | 1390 | |
4f367d8a PZ |
1391 | static int exclusive_bit(int new_bit) |
1392 | { | |
8e18257d | 1393 | /* |
4f367d8a PZ |
1394 | * USED_IN |
1395 | * USED_IN_READ | |
1396 | * ENABLED | |
1397 | * ENABLED_READ | |
1398 | * | |
1399 | * bit 0 - write/read | |
1400 | * bit 1 - used_in/enabled | |
1401 | * bit 2+ state | |
8e18257d | 1402 | */ |
4f367d8a PZ |
1403 | |
1404 | int state = new_bit & ~3; | |
1405 | int dir = new_bit & 2; | |
8e18257d PZ |
1406 | |
1407 | /* | |
4f367d8a | 1408 | * keep state, bit flip the direction and strip read. |
8e18257d | 1409 | */ |
4f367d8a PZ |
1410 | return state | (dir ^ 2); |
1411 | } | |
1412 | ||
1413 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, | |
1414 | struct held_lock *next, enum lock_usage_bit bit) | |
1415 | { | |
8e18257d | 1416 | /* |
4f367d8a PZ |
1417 | * Prove that the new dependency does not connect a hardirq-safe |
1418 | * lock with a hardirq-unsafe lock - to achieve this we search | |
8e18257d PZ |
1419 | * the backwards-subgraph starting at <prev>, and the |
1420 | * forwards-subgraph starting at <next>: | |
1421 | */ | |
4f367d8a PZ |
1422 | if (!check_usage(curr, prev, next, bit, |
1423 | exclusive_bit(bit), state_name(bit))) | |
8e18257d PZ |
1424 | return 0; |
1425 | ||
4f367d8a PZ |
1426 | bit++; /* _READ */ |
1427 | ||
cf40bd16 | 1428 | /* |
4f367d8a PZ |
1429 | * Prove that the new dependency does not connect a hardirq-safe-read |
1430 | * lock with a hardirq-unsafe lock - to achieve this we search | |
cf40bd16 NP |
1431 | * the backwards-subgraph starting at <prev>, and the |
1432 | * forwards-subgraph starting at <next>: | |
1433 | */ | |
4f367d8a PZ |
1434 | if (!check_usage(curr, prev, next, bit, |
1435 | exclusive_bit(bit), state_name(bit))) | |
cf40bd16 NP |
1436 | return 0; |
1437 | ||
4f367d8a PZ |
1438 | return 1; |
1439 | } | |
1440 | ||
1441 | static int | |
1442 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1443 | struct held_lock *next) | |
1444 | { | |
1445 | #define LOCKDEP_STATE(__STATE) \ | |
1446 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ | |
cf40bd16 | 1447 | return 0; |
4f367d8a PZ |
1448 | #include "lockdep_states.h" |
1449 | #undef LOCKDEP_STATE | |
cf40bd16 | 1450 | |
8e18257d PZ |
1451 | return 1; |
1452 | } | |
1453 | ||
1454 | static void inc_chains(void) | |
1455 | { | |
1456 | if (current->hardirq_context) | |
1457 | nr_hardirq_chains++; | |
1458 | else { | |
1459 | if (current->softirq_context) | |
1460 | nr_softirq_chains++; | |
1461 | else | |
1462 | nr_process_chains++; | |
1463 | } | |
1464 | } | |
1465 | ||
1466 | #else | |
1467 | ||
1468 | static inline int | |
1469 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, | |
1470 | struct held_lock *next) | |
1471 | { | |
1472 | return 1; | |
1473 | } | |
1474 | ||
1475 | static inline void inc_chains(void) | |
1476 | { | |
1477 | nr_process_chains++; | |
1478 | } | |
1479 | ||
fbb9ce95 IM |
1480 | #endif |
1481 | ||
1482 | static int | |
1483 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, | |
1484 | struct held_lock *next) | |
1485 | { | |
74c383f1 | 1486 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1487 | return 0; |
1488 | ||
1489 | printk("\n=============================================\n"); | |
1490 | printk( "[ INFO: possible recursive locking detected ]\n"); | |
99de055a | 1491 | print_kernel_version(); |
fbb9ce95 IM |
1492 | printk( "---------------------------------------------\n"); |
1493 | printk("%s/%d is trying to acquire lock:\n", | |
ba25f9dc | 1494 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
1495 | print_lock(next); |
1496 | printk("\nbut task is already holding lock:\n"); | |
1497 | print_lock(prev); | |
1498 | ||
1499 | printk("\nother info that might help us debug this:\n"); | |
1500 | lockdep_print_held_locks(curr); | |
1501 | ||
1502 | printk("\nstack backtrace:\n"); | |
1503 | dump_stack(); | |
1504 | ||
1505 | return 0; | |
1506 | } | |
1507 | ||
1508 | /* | |
1509 | * Check whether we are holding such a class already. | |
1510 | * | |
1511 | * (Note that this has to be done separately, because the graph cannot | |
1512 | * detect such classes of deadlocks.) | |
1513 | * | |
1514 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read | |
1515 | */ | |
1516 | static int | |
1517 | check_deadlock(struct task_struct *curr, struct held_lock *next, | |
1518 | struct lockdep_map *next_instance, int read) | |
1519 | { | |
1520 | struct held_lock *prev; | |
7531e2f3 | 1521 | struct held_lock *nest = NULL; |
fbb9ce95 IM |
1522 | int i; |
1523 | ||
1524 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1525 | prev = curr->held_locks + i; | |
7531e2f3 PZ |
1526 | |
1527 | if (prev->instance == next->nest_lock) | |
1528 | nest = prev; | |
1529 | ||
f82b217e | 1530 | if (hlock_class(prev) != hlock_class(next)) |
fbb9ce95 | 1531 | continue; |
7531e2f3 | 1532 | |
fbb9ce95 IM |
1533 | /* |
1534 | * Allow read-after-read recursion of the same | |
6c9076ec | 1535 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
fbb9ce95 | 1536 | */ |
6c9076ec | 1537 | if ((read == 2) && prev->read) |
fbb9ce95 | 1538 | return 2; |
7531e2f3 PZ |
1539 | |
1540 | /* | |
1541 | * We're holding the nest_lock, which serializes this lock's | |
1542 | * nesting behaviour. | |
1543 | */ | |
1544 | if (nest) | |
1545 | return 2; | |
1546 | ||
fbb9ce95 IM |
1547 | return print_deadlock_bug(curr, prev, next); |
1548 | } | |
1549 | return 1; | |
1550 | } | |
1551 | ||
1552 | /* | |
1553 | * There was a chain-cache miss, and we are about to add a new dependency | |
1554 | * to a previous lock. We recursively validate the following rules: | |
1555 | * | |
1556 | * - would the adding of the <prev> -> <next> dependency create a | |
1557 | * circular dependency in the graph? [== circular deadlock] | |
1558 | * | |
1559 | * - does the new prev->next dependency connect any hardirq-safe lock | |
1560 | * (in the full backwards-subgraph starting at <prev>) with any | |
1561 | * hardirq-unsafe lock (in the full forwards-subgraph starting at | |
1562 | * <next>)? [== illegal lock inversion with hardirq contexts] | |
1563 | * | |
1564 | * - does the new prev->next dependency connect any softirq-safe lock | |
1565 | * (in the full backwards-subgraph starting at <prev>) with any | |
1566 | * softirq-unsafe lock (in the full forwards-subgraph starting at | |
1567 | * <next>)? [== illegal lock inversion with softirq contexts] | |
1568 | * | |
1569 | * any of these scenarios could lead to a deadlock. | |
1570 | * | |
1571 | * Then if all the validations pass, we add the forwards and backwards | |
1572 | * dependency. | |
1573 | */ | |
1574 | static int | |
1575 | check_prev_add(struct task_struct *curr, struct held_lock *prev, | |
068135e6 | 1576 | struct held_lock *next, int distance) |
fbb9ce95 IM |
1577 | { |
1578 | struct lock_list *entry; | |
1579 | int ret; | |
1580 | ||
1581 | /* | |
1582 | * Prove that the new <prev> -> <next> dependency would not | |
1583 | * create a circular dependency in the graph. (We do this by | |
1584 | * forward-recursing into the graph starting at <next>, and | |
1585 | * checking whether we can reach <prev>.) | |
1586 | * | |
1587 | * We are using global variables to control the recursion, to | |
1588 | * keep the stackframe size of the recursive functions low: | |
1589 | */ | |
1590 | check_source = next; | |
1591 | check_target = prev; | |
d588e461 | 1592 | |
c94aa5ca ML |
1593 | if (check_noncircular(hlock_class(next), 0) == 2) |
1594 | return print_circular_bug(); | |
1595 | ||
8e18257d | 1596 | if (!check_prev_add_irq(curr, prev, next)) |
fbb9ce95 IM |
1597 | return 0; |
1598 | ||
fbb9ce95 IM |
1599 | /* |
1600 | * For recursive read-locks we do all the dependency checks, | |
1601 | * but we dont store read-triggered dependencies (only | |
1602 | * write-triggered dependencies). This ensures that only the | |
1603 | * write-side dependencies matter, and that if for example a | |
1604 | * write-lock never takes any other locks, then the reads are | |
1605 | * equivalent to a NOP. | |
1606 | */ | |
1607 | if (next->read == 2 || prev->read == 2) | |
1608 | return 1; | |
1609 | /* | |
1610 | * Is the <prev> -> <next> dependency already present? | |
1611 | * | |
1612 | * (this may occur even though this is a new chain: consider | |
1613 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 | |
1614 | * chains - the second one will be new, but L1 already has | |
1615 | * L2 added to its dependency list, due to the first chain.) | |
1616 | */ | |
f82b217e DJ |
1617 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
1618 | if (entry->class == hlock_class(next)) { | |
068135e6 JB |
1619 | if (distance == 1) |
1620 | entry->distance = 1; | |
fbb9ce95 | 1621 | return 2; |
068135e6 | 1622 | } |
fbb9ce95 IM |
1623 | } |
1624 | ||
1625 | /* | |
1626 | * Ok, all validations passed, add the new lock | |
1627 | * to the previous lock's dependency list: | |
1628 | */ | |
f82b217e DJ |
1629 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
1630 | &hlock_class(prev)->locks_after, | |
1631 | next->acquire_ip, distance); | |
068135e6 | 1632 | |
fbb9ce95 IM |
1633 | if (!ret) |
1634 | return 0; | |
910b1b2e | 1635 | |
f82b217e DJ |
1636 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
1637 | &hlock_class(next)->locks_before, | |
1638 | next->acquire_ip, distance); | |
910b1b2e JP |
1639 | if (!ret) |
1640 | return 0; | |
fbb9ce95 IM |
1641 | |
1642 | /* | |
8e18257d PZ |
1643 | * Debugging printouts: |
1644 | */ | |
f82b217e | 1645 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
8e18257d PZ |
1646 | graph_unlock(); |
1647 | printk("\n new dependency: "); | |
f82b217e | 1648 | print_lock_name(hlock_class(prev)); |
8e18257d | 1649 | printk(" => "); |
f82b217e | 1650 | print_lock_name(hlock_class(next)); |
8e18257d | 1651 | printk("\n"); |
fbb9ce95 | 1652 | dump_stack(); |
8e18257d | 1653 | return graph_lock(); |
fbb9ce95 | 1654 | } |
8e18257d PZ |
1655 | return 1; |
1656 | } | |
fbb9ce95 | 1657 | |
8e18257d PZ |
1658 | /* |
1659 | * Add the dependency to all directly-previous locks that are 'relevant'. | |
1660 | * The ones that are relevant are (in increasing distance from curr): | |
1661 | * all consecutive trylock entries and the final non-trylock entry - or | |
1662 | * the end of this context's lock-chain - whichever comes first. | |
1663 | */ | |
1664 | static int | |
1665 | check_prevs_add(struct task_struct *curr, struct held_lock *next) | |
1666 | { | |
1667 | int depth = curr->lockdep_depth; | |
1668 | struct held_lock *hlock; | |
d6d897ce | 1669 | |
fbb9ce95 | 1670 | /* |
8e18257d PZ |
1671 | * Debugging checks. |
1672 | * | |
1673 | * Depth must not be zero for a non-head lock: | |
fbb9ce95 | 1674 | */ |
8e18257d PZ |
1675 | if (!depth) |
1676 | goto out_bug; | |
fbb9ce95 | 1677 | /* |
8e18257d PZ |
1678 | * At least two relevant locks must exist for this |
1679 | * to be a head: | |
fbb9ce95 | 1680 | */ |
8e18257d PZ |
1681 | if (curr->held_locks[depth].irq_context != |
1682 | curr->held_locks[depth-1].irq_context) | |
1683 | goto out_bug; | |
74c383f1 | 1684 | |
8e18257d PZ |
1685 | for (;;) { |
1686 | int distance = curr->lockdep_depth - depth + 1; | |
1687 | hlock = curr->held_locks + depth-1; | |
1688 | /* | |
1689 | * Only non-recursive-read entries get new dependencies | |
1690 | * added: | |
1691 | */ | |
1692 | if (hlock->read != 2) { | |
1693 | if (!check_prev_add(curr, hlock, next, distance)) | |
1694 | return 0; | |
1695 | /* | |
1696 | * Stop after the first non-trylock entry, | |
1697 | * as non-trylock entries have added their | |
1698 | * own direct dependencies already, so this | |
1699 | * lock is connected to them indirectly: | |
1700 | */ | |
1701 | if (!hlock->trylock) | |
1702 | break; | |
74c383f1 | 1703 | } |
8e18257d PZ |
1704 | depth--; |
1705 | /* | |
1706 | * End of lock-stack? | |
1707 | */ | |
1708 | if (!depth) | |
1709 | break; | |
1710 | /* | |
1711 | * Stop the search if we cross into another context: | |
1712 | */ | |
1713 | if (curr->held_locks[depth].irq_context != | |
1714 | curr->held_locks[depth-1].irq_context) | |
1715 | break; | |
fbb9ce95 | 1716 | } |
8e18257d PZ |
1717 | return 1; |
1718 | out_bug: | |
1719 | if (!debug_locks_off_graph_unlock()) | |
1720 | return 0; | |
fbb9ce95 | 1721 | |
8e18257d | 1722 | WARN_ON(1); |
fbb9ce95 | 1723 | |
8e18257d | 1724 | return 0; |
fbb9ce95 IM |
1725 | } |
1726 | ||
8e18257d | 1727 | unsigned long nr_lock_chains; |
443cd507 | 1728 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
cd1a28e8 | 1729 | int nr_chain_hlocks; |
443cd507 HY |
1730 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
1731 | ||
1732 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) | |
1733 | { | |
1734 | return lock_classes + chain_hlocks[chain->base + i]; | |
1735 | } | |
8e18257d | 1736 | |
fbb9ce95 IM |
1737 | /* |
1738 | * Look up a dependency chain. If the key is not present yet then | |
9e860d00 JP |
1739 | * add it and return 1 - in this case the new dependency chain is |
1740 | * validated. If the key is already hashed, return 0. | |
1741 | * (On return with 1 graph_lock is held.) | |
fbb9ce95 | 1742 | */ |
443cd507 HY |
1743 | static inline int lookup_chain_cache(struct task_struct *curr, |
1744 | struct held_lock *hlock, | |
1745 | u64 chain_key) | |
fbb9ce95 | 1746 | { |
f82b217e | 1747 | struct lock_class *class = hlock_class(hlock); |
fbb9ce95 IM |
1748 | struct list_head *hash_head = chainhashentry(chain_key); |
1749 | struct lock_chain *chain; | |
443cd507 | 1750 | struct held_lock *hlock_curr, *hlock_next; |
cd1a28e8 | 1751 | int i, j, n, cn; |
fbb9ce95 | 1752 | |
381a2292 JP |
1753 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
1754 | return 0; | |
fbb9ce95 IM |
1755 | /* |
1756 | * We can walk it lock-free, because entries only get added | |
1757 | * to the hash: | |
1758 | */ | |
1759 | list_for_each_entry(chain, hash_head, entry) { | |
1760 | if (chain->chain_key == chain_key) { | |
1761 | cache_hit: | |
1762 | debug_atomic_inc(&chain_lookup_hits); | |
81fc685a | 1763 | if (very_verbose(class)) |
755cd900 AM |
1764 | printk("\nhash chain already cached, key: " |
1765 | "%016Lx tail class: [%p] %s\n", | |
1766 | (unsigned long long)chain_key, | |
1767 | class->key, class->name); | |
fbb9ce95 IM |
1768 | return 0; |
1769 | } | |
1770 | } | |
81fc685a | 1771 | if (very_verbose(class)) |
755cd900 AM |
1772 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
1773 | (unsigned long long)chain_key, class->key, class->name); | |
fbb9ce95 IM |
1774 | /* |
1775 | * Allocate a new chain entry from the static array, and add | |
1776 | * it to the hash: | |
1777 | */ | |
74c383f1 IM |
1778 | if (!graph_lock()) |
1779 | return 0; | |
fbb9ce95 IM |
1780 | /* |
1781 | * We have to walk the chain again locked - to avoid duplicates: | |
1782 | */ | |
1783 | list_for_each_entry(chain, hash_head, entry) { | |
1784 | if (chain->chain_key == chain_key) { | |
74c383f1 | 1785 | graph_unlock(); |
fbb9ce95 IM |
1786 | goto cache_hit; |
1787 | } | |
1788 | } | |
1789 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { | |
74c383f1 IM |
1790 | if (!debug_locks_off_graph_unlock()) |
1791 | return 0; | |
1792 | ||
fbb9ce95 IM |
1793 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
1794 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 1795 | dump_stack(); |
fbb9ce95 IM |
1796 | return 0; |
1797 | } | |
1798 | chain = lock_chains + nr_lock_chains++; | |
1799 | chain->chain_key = chain_key; | |
443cd507 HY |
1800 | chain->irq_context = hlock->irq_context; |
1801 | /* Find the first held_lock of current chain */ | |
1802 | hlock_next = hlock; | |
1803 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { | |
1804 | hlock_curr = curr->held_locks + i; | |
1805 | if (hlock_curr->irq_context != hlock_next->irq_context) | |
1806 | break; | |
1807 | hlock_next = hlock; | |
1808 | } | |
1809 | i++; | |
1810 | chain->depth = curr->lockdep_depth + 1 - i; | |
cd1a28e8 HY |
1811 | cn = nr_chain_hlocks; |
1812 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { | |
1813 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); | |
1814 | if (n == cn) | |
1815 | break; | |
1816 | cn = n; | |
1817 | } | |
1818 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { | |
1819 | chain->base = cn; | |
443cd507 | 1820 | for (j = 0; j < chain->depth - 1; j++, i++) { |
f82b217e | 1821 | int lock_id = curr->held_locks[i].class_idx - 1; |
443cd507 HY |
1822 | chain_hlocks[chain->base + j] = lock_id; |
1823 | } | |
1824 | chain_hlocks[chain->base + j] = class - lock_classes; | |
1825 | } | |
fbb9ce95 IM |
1826 | list_add_tail_rcu(&chain->entry, hash_head); |
1827 | debug_atomic_inc(&chain_lookup_misses); | |
8e18257d PZ |
1828 | inc_chains(); |
1829 | ||
1830 | return 1; | |
1831 | } | |
1832 | ||
1833 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, | |
4e6045f1 | 1834 | struct held_lock *hlock, int chain_head, u64 chain_key) |
8e18257d PZ |
1835 | { |
1836 | /* | |
1837 | * Trylock needs to maintain the stack of held locks, but it | |
1838 | * does not add new dependencies, because trylock can be done | |
1839 | * in any order. | |
1840 | * | |
1841 | * We look up the chain_key and do the O(N^2) check and update of | |
1842 | * the dependencies only if this is a new dependency chain. | |
1843 | * (If lookup_chain_cache() returns with 1 it acquires | |
1844 | * graph_lock for us) | |
1845 | */ | |
1846 | if (!hlock->trylock && (hlock->check == 2) && | |
443cd507 | 1847 | lookup_chain_cache(curr, hlock, chain_key)) { |
8e18257d PZ |
1848 | /* |
1849 | * Check whether last held lock: | |
1850 | * | |
1851 | * - is irq-safe, if this lock is irq-unsafe | |
1852 | * - is softirq-safe, if this lock is hardirq-unsafe | |
1853 | * | |
1854 | * And check whether the new lock's dependency graph | |
1855 | * could lead back to the previous lock. | |
1856 | * | |
1857 | * any of these scenarios could lead to a deadlock. If | |
1858 | * All validations | |
1859 | */ | |
1860 | int ret = check_deadlock(curr, hlock, lock, hlock->read); | |
1861 | ||
1862 | if (!ret) | |
1863 | return 0; | |
1864 | /* | |
1865 | * Mark recursive read, as we jump over it when | |
1866 | * building dependencies (just like we jump over | |
1867 | * trylock entries): | |
1868 | */ | |
1869 | if (ret == 2) | |
1870 | hlock->read = 2; | |
1871 | /* | |
1872 | * Add dependency only if this lock is not the head | |
1873 | * of the chain, and if it's not a secondary read-lock: | |
1874 | */ | |
1875 | if (!chain_head && ret != 2) | |
1876 | if (!check_prevs_add(curr, hlock)) | |
1877 | return 0; | |
1878 | graph_unlock(); | |
1879 | } else | |
1880 | /* after lookup_chain_cache(): */ | |
1881 | if (unlikely(!debug_locks)) | |
1882 | return 0; | |
fbb9ce95 IM |
1883 | |
1884 | return 1; | |
1885 | } | |
8e18257d PZ |
1886 | #else |
1887 | static inline int validate_chain(struct task_struct *curr, | |
1888 | struct lockdep_map *lock, struct held_lock *hlock, | |
3aa416b0 | 1889 | int chain_head, u64 chain_key) |
8e18257d PZ |
1890 | { |
1891 | return 1; | |
1892 | } | |
ca58abcb | 1893 | #endif |
fbb9ce95 IM |
1894 | |
1895 | /* | |
1896 | * We are building curr_chain_key incrementally, so double-check | |
1897 | * it from scratch, to make sure that it's done correctly: | |
1898 | */ | |
1d09daa5 | 1899 | static void check_chain_key(struct task_struct *curr) |
fbb9ce95 IM |
1900 | { |
1901 | #ifdef CONFIG_DEBUG_LOCKDEP | |
1902 | struct held_lock *hlock, *prev_hlock = NULL; | |
1903 | unsigned int i, id; | |
1904 | u64 chain_key = 0; | |
1905 | ||
1906 | for (i = 0; i < curr->lockdep_depth; i++) { | |
1907 | hlock = curr->held_locks + i; | |
1908 | if (chain_key != hlock->prev_chain_key) { | |
1909 | debug_locks_off(); | |
2df8b1d6 | 1910 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1911 | curr->lockdep_depth, i, |
1912 | (unsigned long long)chain_key, | |
1913 | (unsigned long long)hlock->prev_chain_key); | |
fbb9ce95 IM |
1914 | return; |
1915 | } | |
f82b217e | 1916 | id = hlock->class_idx - 1; |
381a2292 JP |
1917 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
1918 | return; | |
1919 | ||
fbb9ce95 IM |
1920 | if (prev_hlock && (prev_hlock->irq_context != |
1921 | hlock->irq_context)) | |
1922 | chain_key = 0; | |
1923 | chain_key = iterate_chain_key(chain_key, id); | |
1924 | prev_hlock = hlock; | |
1925 | } | |
1926 | if (chain_key != curr->curr_chain_key) { | |
1927 | debug_locks_off(); | |
2df8b1d6 | 1928 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
fbb9ce95 IM |
1929 | curr->lockdep_depth, i, |
1930 | (unsigned long long)chain_key, | |
1931 | (unsigned long long)curr->curr_chain_key); | |
fbb9ce95 IM |
1932 | } |
1933 | #endif | |
1934 | } | |
1935 | ||
8e18257d PZ |
1936 | static int |
1937 | print_usage_bug(struct task_struct *curr, struct held_lock *this, | |
1938 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) | |
1939 | { | |
1940 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) | |
1941 | return 0; | |
1942 | ||
1943 | printk("\n=================================\n"); | |
1944 | printk( "[ INFO: inconsistent lock state ]\n"); | |
1945 | print_kernel_version(); | |
1946 | printk( "---------------------------------\n"); | |
1947 | ||
1948 | printk("inconsistent {%s} -> {%s} usage.\n", | |
1949 | usage_str[prev_bit], usage_str[new_bit]); | |
1950 | ||
1951 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", | |
ba25f9dc | 1952 | curr->comm, task_pid_nr(curr), |
8e18257d PZ |
1953 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
1954 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, | |
1955 | trace_hardirqs_enabled(curr), | |
1956 | trace_softirqs_enabled(curr)); | |
1957 | print_lock(this); | |
1958 | ||
1959 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); | |
f82b217e | 1960 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
8e18257d PZ |
1961 | |
1962 | print_irqtrace_events(curr); | |
1963 | printk("\nother info that might help us debug this:\n"); | |
1964 | lockdep_print_held_locks(curr); | |
1965 | ||
1966 | printk("\nstack backtrace:\n"); | |
1967 | dump_stack(); | |
1968 | ||
1969 | return 0; | |
1970 | } | |
1971 | ||
1972 | /* | |
1973 | * Print out an error if an invalid bit is set: | |
1974 | */ | |
1975 | static inline int | |
1976 | valid_state(struct task_struct *curr, struct held_lock *this, | |
1977 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) | |
1978 | { | |
f82b217e | 1979 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
8e18257d PZ |
1980 | return print_usage_bug(curr, this, bad_bit, new_bit); |
1981 | return 1; | |
1982 | } | |
1983 | ||
1984 | static int mark_lock(struct task_struct *curr, struct held_lock *this, | |
1985 | enum lock_usage_bit new_bit); | |
1986 | ||
81d68a96 | 1987 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
fbb9ce95 IM |
1988 | |
1989 | /* | |
1990 | * print irq inversion bug: | |
1991 | */ | |
1992 | static int | |
1993 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, | |
1994 | struct held_lock *this, int forwards, | |
1995 | const char *irqclass) | |
1996 | { | |
74c383f1 | 1997 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
fbb9ce95 IM |
1998 | return 0; |
1999 | ||
2000 | printk("\n=========================================================\n"); | |
2001 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); | |
99de055a | 2002 | print_kernel_version(); |
fbb9ce95 IM |
2003 | printk( "---------------------------------------------------------\n"); |
2004 | printk("%s/%d just changed the state of lock:\n", | |
ba25f9dc | 2005 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2006 | print_lock(this); |
2007 | if (forwards) | |
26575e28 | 2008 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
fbb9ce95 | 2009 | else |
26575e28 | 2010 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
fbb9ce95 IM |
2011 | print_lock_name(other); |
2012 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); | |
2013 | ||
2014 | printk("\nother info that might help us debug this:\n"); | |
2015 | lockdep_print_held_locks(curr); | |
2016 | ||
2017 | printk("\nthe first lock's dependencies:\n"); | |
f82b217e | 2018 | print_lock_dependencies(hlock_class(this), 0); |
fbb9ce95 IM |
2019 | |
2020 | printk("\nthe second lock's dependencies:\n"); | |
2021 | print_lock_dependencies(other, 0); | |
2022 | ||
2023 | printk("\nstack backtrace:\n"); | |
2024 | dump_stack(); | |
2025 | ||
2026 | return 0; | |
2027 | } | |
2028 | ||
2029 | /* | |
2030 | * Prove that in the forwards-direction subgraph starting at <this> | |
2031 | * there is no lock matching <mask>: | |
2032 | */ | |
2033 | static int | |
2034 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, | |
2035 | enum lock_usage_bit bit, const char *irqclass) | |
2036 | { | |
2037 | int ret; | |
2038 | ||
2039 | find_usage_bit = bit; | |
2040 | /* fills in <forwards_match> */ | |
f82b217e | 2041 | ret = find_usage_forwards(hlock_class(this), 0); |
fbb9ce95 IM |
2042 | if (!ret || ret == 1) |
2043 | return ret; | |
2044 | ||
2045 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); | |
2046 | } | |
2047 | ||
2048 | /* | |
2049 | * Prove that in the backwards-direction subgraph starting at <this> | |
2050 | * there is no lock matching <mask>: | |
2051 | */ | |
2052 | static int | |
2053 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, | |
2054 | enum lock_usage_bit bit, const char *irqclass) | |
2055 | { | |
2056 | int ret; | |
2057 | ||
2058 | find_usage_bit = bit; | |
2059 | /* fills in <backwards_match> */ | |
f82b217e | 2060 | ret = find_usage_backwards(hlock_class(this), 0); |
fbb9ce95 IM |
2061 | if (!ret || ret == 1) |
2062 | return ret; | |
2063 | ||
2064 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); | |
2065 | } | |
2066 | ||
3117df04 | 2067 | void print_irqtrace_events(struct task_struct *curr) |
fbb9ce95 IM |
2068 | { |
2069 | printk("irq event stamp: %u\n", curr->irq_events); | |
2070 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); | |
2071 | print_ip_sym(curr->hardirq_enable_ip); | |
2072 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); | |
2073 | print_ip_sym(curr->hardirq_disable_ip); | |
2074 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); | |
2075 | print_ip_sym(curr->softirq_enable_ip); | |
2076 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); | |
2077 | print_ip_sym(curr->softirq_disable_ip); | |
2078 | } | |
2079 | ||
cd95302d | 2080 | static int HARDIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2081 | { |
8e18257d PZ |
2082 | #if HARDIRQ_VERBOSE |
2083 | return class_filter(class); | |
2084 | #endif | |
fbb9ce95 IM |
2085 | return 0; |
2086 | } | |
2087 | ||
cd95302d | 2088 | static int SOFTIRQ_verbose(struct lock_class *class) |
fbb9ce95 | 2089 | { |
8e18257d PZ |
2090 | #if SOFTIRQ_VERBOSE |
2091 | return class_filter(class); | |
2092 | #endif | |
2093 | return 0; | |
fbb9ce95 IM |
2094 | } |
2095 | ||
cd95302d | 2096 | static int RECLAIM_FS_verbose(struct lock_class *class) |
cf40bd16 NP |
2097 | { |
2098 | #if RECLAIM_VERBOSE | |
2099 | return class_filter(class); | |
2100 | #endif | |
2101 | return 0; | |
2102 | } | |
2103 | ||
fbb9ce95 IM |
2104 | #define STRICT_READ_CHECKS 1 |
2105 | ||
cd95302d PZ |
2106 | static int (*state_verbose_f[])(struct lock_class *class) = { |
2107 | #define LOCKDEP_STATE(__STATE) \ | |
2108 | __STATE##_verbose, | |
2109 | #include "lockdep_states.h" | |
2110 | #undef LOCKDEP_STATE | |
2111 | }; | |
2112 | ||
2113 | static inline int state_verbose(enum lock_usage_bit bit, | |
2114 | struct lock_class *class) | |
2115 | { | |
2116 | return state_verbose_f[bit >> 2](class); | |
2117 | } | |
2118 | ||
42c50d54 PZ |
2119 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
2120 | enum lock_usage_bit bit, const char *name); | |
2121 | ||
6a6904d3 | 2122 | static int |
1c21f14e PZ |
2123 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
2124 | enum lock_usage_bit new_bit) | |
6a6904d3 | 2125 | { |
f989209e | 2126 | int excl_bit = exclusive_bit(new_bit); |
9d3651a2 | 2127 | int read = new_bit & 1; |
42c50d54 PZ |
2128 | int dir = new_bit & 2; |
2129 | ||
38aa2714 PZ |
2130 | /* |
2131 | * mark USED_IN has to look forwards -- to ensure no dependency | |
2132 | * has ENABLED state, which would allow recursion deadlocks. | |
2133 | * | |
2134 | * mark ENABLED has to look backwards -- to ensure no dependee | |
2135 | * has USED_IN state, which, again, would allow recursion deadlocks. | |
2136 | */ | |
42c50d54 PZ |
2137 | check_usage_f usage = dir ? |
2138 | check_usage_backwards : check_usage_forwards; | |
f989209e | 2139 | |
38aa2714 PZ |
2140 | /* |
2141 | * Validate that this particular lock does not have conflicting | |
2142 | * usage states. | |
2143 | */ | |
6a6904d3 PZ |
2144 | if (!valid_state(curr, this, new_bit, excl_bit)) |
2145 | return 0; | |
42c50d54 | 2146 | |
38aa2714 PZ |
2147 | /* |
2148 | * Validate that the lock dependencies don't have conflicting usage | |
2149 | * states. | |
2150 | */ | |
2151 | if ((!read || !dir || STRICT_READ_CHECKS) && | |
1c21f14e | 2152 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
6a6904d3 | 2153 | return 0; |
780e820b | 2154 | |
38aa2714 PZ |
2155 | /* |
2156 | * Check for read in write conflicts | |
2157 | */ | |
2158 | if (!read) { | |
2159 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) | |
2160 | return 0; | |
2161 | ||
2162 | if (STRICT_READ_CHECKS && | |
4f367d8a PZ |
2163 | !usage(curr, this, excl_bit + 1, |
2164 | state_name(new_bit + 1))) | |
38aa2714 PZ |
2165 | return 0; |
2166 | } | |
780e820b | 2167 | |
cd95302d | 2168 | if (state_verbose(new_bit, hlock_class(this))) |
6a6904d3 PZ |
2169 | return 2; |
2170 | ||
2171 | return 1; | |
2172 | } | |
2173 | ||
cf40bd16 | 2174 | enum mark_type { |
36bfb9bb PZ |
2175 | #define LOCKDEP_STATE(__STATE) __STATE, |
2176 | #include "lockdep_states.h" | |
2177 | #undef LOCKDEP_STATE | |
cf40bd16 NP |
2178 | }; |
2179 | ||
fbb9ce95 IM |
2180 | /* |
2181 | * Mark all held locks with a usage bit: | |
2182 | */ | |
1d09daa5 | 2183 | static int |
cf40bd16 | 2184 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
fbb9ce95 IM |
2185 | { |
2186 | enum lock_usage_bit usage_bit; | |
2187 | struct held_lock *hlock; | |
2188 | int i; | |
2189 | ||
2190 | for (i = 0; i < curr->lockdep_depth; i++) { | |
2191 | hlock = curr->held_locks + i; | |
2192 | ||
cf2ad4d1 PZ |
2193 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
2194 | if (hlock->read) | |
2195 | usage_bit += 1; /* READ */ | |
2196 | ||
2197 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); | |
cf40bd16 | 2198 | |
4ff773bb | 2199 | if (!mark_lock(curr, hlock, usage_bit)) |
fbb9ce95 IM |
2200 | return 0; |
2201 | } | |
2202 | ||
2203 | return 1; | |
2204 | } | |
2205 | ||
2206 | /* | |
2207 | * Debugging helper: via this flag we know that we are in | |
2208 | * 'early bootup code', and will warn about any invalid irqs-on event: | |
2209 | */ | |
2210 | static int early_boot_irqs_enabled; | |
2211 | ||
2212 | void early_boot_irqs_off(void) | |
2213 | { | |
2214 | early_boot_irqs_enabled = 0; | |
2215 | } | |
2216 | ||
2217 | void early_boot_irqs_on(void) | |
2218 | { | |
2219 | early_boot_irqs_enabled = 1; | |
2220 | } | |
2221 | ||
2222 | /* | |
2223 | * Hardirqs will be enabled: | |
2224 | */ | |
6afe40b4 | 2225 | void trace_hardirqs_on_caller(unsigned long ip) |
fbb9ce95 IM |
2226 | { |
2227 | struct task_struct *curr = current; | |
fbb9ce95 | 2228 | |
6afe40b4 | 2229 | time_hardirqs_on(CALLER_ADDR0, ip); |
81d68a96 | 2230 | |
fbb9ce95 IM |
2231 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2232 | return; | |
2233 | ||
2234 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) | |
2235 | return; | |
2236 | ||
2237 | if (unlikely(curr->hardirqs_enabled)) { | |
2238 | debug_atomic_inc(&redundant_hardirqs_on); | |
2239 | return; | |
2240 | } | |
2241 | /* we'll do an OFF -> ON transition: */ | |
2242 | curr->hardirqs_enabled = 1; | |
fbb9ce95 IM |
2243 | |
2244 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2245 | return; | |
2246 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) | |
2247 | return; | |
2248 | /* | |
2249 | * We are going to turn hardirqs on, so set the | |
2250 | * usage bit for all held locks: | |
2251 | */ | |
cf40bd16 | 2252 | if (!mark_held_locks(curr, HARDIRQ)) |
fbb9ce95 IM |
2253 | return; |
2254 | /* | |
2255 | * If we have softirqs enabled, then set the usage | |
2256 | * bit for all held locks. (disabled hardirqs prevented | |
2257 | * this bit from being set before) | |
2258 | */ | |
2259 | if (curr->softirqs_enabled) | |
cf40bd16 | 2260 | if (!mark_held_locks(curr, SOFTIRQ)) |
fbb9ce95 IM |
2261 | return; |
2262 | ||
8e18257d PZ |
2263 | curr->hardirq_enable_ip = ip; |
2264 | curr->hardirq_enable_event = ++curr->irq_events; | |
2265 | debug_atomic_inc(&hardirqs_on_events); | |
2266 | } | |
81d68a96 | 2267 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
8e18257d | 2268 | |
1d09daa5 | 2269 | void trace_hardirqs_on(void) |
81d68a96 SR |
2270 | { |
2271 | trace_hardirqs_on_caller(CALLER_ADDR0); | |
2272 | } | |
8e18257d PZ |
2273 | EXPORT_SYMBOL(trace_hardirqs_on); |
2274 | ||
2275 | /* | |
2276 | * Hardirqs were disabled: | |
2277 | */ | |
6afe40b4 | 2278 | void trace_hardirqs_off_caller(unsigned long ip) |
8e18257d PZ |
2279 | { |
2280 | struct task_struct *curr = current; | |
2281 | ||
6afe40b4 | 2282 | time_hardirqs_off(CALLER_ADDR0, ip); |
81d68a96 | 2283 | |
8e18257d PZ |
2284 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
2285 | return; | |
2286 | ||
2287 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2288 | return; | |
2289 | ||
2290 | if (curr->hardirqs_enabled) { | |
2291 | /* | |
2292 | * We have done an ON -> OFF transition: | |
2293 | */ | |
2294 | curr->hardirqs_enabled = 0; | |
6afe40b4 | 2295 | curr->hardirq_disable_ip = ip; |
8e18257d PZ |
2296 | curr->hardirq_disable_event = ++curr->irq_events; |
2297 | debug_atomic_inc(&hardirqs_off_events); | |
2298 | } else | |
2299 | debug_atomic_inc(&redundant_hardirqs_off); | |
2300 | } | |
81d68a96 | 2301 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
8e18257d | 2302 | |
1d09daa5 | 2303 | void trace_hardirqs_off(void) |
81d68a96 SR |
2304 | { |
2305 | trace_hardirqs_off_caller(CALLER_ADDR0); | |
2306 | } | |
8e18257d PZ |
2307 | EXPORT_SYMBOL(trace_hardirqs_off); |
2308 | ||
2309 | /* | |
2310 | * Softirqs will be enabled: | |
2311 | */ | |
2312 | void trace_softirqs_on(unsigned long ip) | |
2313 | { | |
2314 | struct task_struct *curr = current; | |
2315 | ||
2316 | if (unlikely(!debug_locks)) | |
2317 | return; | |
2318 | ||
2319 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2320 | return; | |
2321 | ||
2322 | if (curr->softirqs_enabled) { | |
2323 | debug_atomic_inc(&redundant_softirqs_on); | |
2324 | return; | |
2325 | } | |
2326 | ||
2327 | /* | |
2328 | * We'll do an OFF -> ON transition: | |
2329 | */ | |
2330 | curr->softirqs_enabled = 1; | |
2331 | curr->softirq_enable_ip = ip; | |
2332 | curr->softirq_enable_event = ++curr->irq_events; | |
2333 | debug_atomic_inc(&softirqs_on_events); | |
2334 | /* | |
2335 | * We are going to turn softirqs on, so set the | |
2336 | * usage bit for all held locks, if hardirqs are | |
2337 | * enabled too: | |
2338 | */ | |
2339 | if (curr->hardirqs_enabled) | |
cf40bd16 | 2340 | mark_held_locks(curr, SOFTIRQ); |
8e18257d PZ |
2341 | } |
2342 | ||
2343 | /* | |
2344 | * Softirqs were disabled: | |
2345 | */ | |
2346 | void trace_softirqs_off(unsigned long ip) | |
2347 | { | |
2348 | struct task_struct *curr = current; | |
2349 | ||
2350 | if (unlikely(!debug_locks)) | |
2351 | return; | |
2352 | ||
2353 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2354 | return; | |
2355 | ||
2356 | if (curr->softirqs_enabled) { | |
2357 | /* | |
2358 | * We have done an ON -> OFF transition: | |
2359 | */ | |
2360 | curr->softirqs_enabled = 0; | |
2361 | curr->softirq_disable_ip = ip; | |
2362 | curr->softirq_disable_event = ++curr->irq_events; | |
2363 | debug_atomic_inc(&softirqs_off_events); | |
2364 | DEBUG_LOCKS_WARN_ON(!softirq_count()); | |
2365 | } else | |
2366 | debug_atomic_inc(&redundant_softirqs_off); | |
2367 | } | |
2368 | ||
2f850181 | 2369 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
cf40bd16 NP |
2370 | { |
2371 | struct task_struct *curr = current; | |
2372 | ||
2373 | if (unlikely(!debug_locks)) | |
2374 | return; | |
2375 | ||
2376 | /* no reclaim without waiting on it */ | |
2377 | if (!(gfp_mask & __GFP_WAIT)) | |
2378 | return; | |
2379 | ||
2380 | /* this guy won't enter reclaim */ | |
2381 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) | |
2382 | return; | |
2383 | ||
2384 | /* We're only interested __GFP_FS allocations for now */ | |
2385 | if (!(gfp_mask & __GFP_FS)) | |
2386 | return; | |
2387 | ||
2f850181 | 2388 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
cf40bd16 NP |
2389 | return; |
2390 | ||
2391 | mark_held_locks(curr, RECLAIM_FS); | |
2392 | } | |
2393 | ||
2f850181 PZ |
2394 | static void check_flags(unsigned long flags); |
2395 | ||
2396 | void lockdep_trace_alloc(gfp_t gfp_mask) | |
2397 | { | |
2398 | unsigned long flags; | |
2399 | ||
2400 | if (unlikely(current->lockdep_recursion)) | |
2401 | return; | |
2402 | ||
2403 | raw_local_irq_save(flags); | |
2404 | check_flags(flags); | |
2405 | current->lockdep_recursion = 1; | |
2406 | __lockdep_trace_alloc(gfp_mask, flags); | |
2407 | current->lockdep_recursion = 0; | |
2408 | raw_local_irq_restore(flags); | |
2409 | } | |
2410 | ||
8e18257d PZ |
2411 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
2412 | { | |
2413 | /* | |
2414 | * If non-trylock use in a hardirq or softirq context, then | |
2415 | * mark the lock as used in these contexts: | |
2416 | */ | |
2417 | if (!hlock->trylock) { | |
2418 | if (hlock->read) { | |
2419 | if (curr->hardirq_context) | |
2420 | if (!mark_lock(curr, hlock, | |
2421 | LOCK_USED_IN_HARDIRQ_READ)) | |
2422 | return 0; | |
2423 | if (curr->softirq_context) | |
2424 | if (!mark_lock(curr, hlock, | |
2425 | LOCK_USED_IN_SOFTIRQ_READ)) | |
2426 | return 0; | |
2427 | } else { | |
2428 | if (curr->hardirq_context) | |
2429 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) | |
2430 | return 0; | |
2431 | if (curr->softirq_context) | |
2432 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) | |
2433 | return 0; | |
2434 | } | |
2435 | } | |
2436 | if (!hlock->hardirqs_off) { | |
2437 | if (hlock->read) { | |
2438 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2439 | LOCK_ENABLED_HARDIRQ_READ)) |
8e18257d PZ |
2440 | return 0; |
2441 | if (curr->softirqs_enabled) | |
2442 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2443 | LOCK_ENABLED_SOFTIRQ_READ)) |
8e18257d PZ |
2444 | return 0; |
2445 | } else { | |
2446 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2447 | LOCK_ENABLED_HARDIRQ)) |
8e18257d PZ |
2448 | return 0; |
2449 | if (curr->softirqs_enabled) | |
2450 | if (!mark_lock(curr, hlock, | |
4fc95e86 | 2451 | LOCK_ENABLED_SOFTIRQ)) |
8e18257d PZ |
2452 | return 0; |
2453 | } | |
2454 | } | |
2455 | ||
cf40bd16 NP |
2456 | /* |
2457 | * We reuse the irq context infrastructure more broadly as a general | |
2458 | * context checking code. This tests GFP_FS recursion (a lock taken | |
2459 | * during reclaim for a GFP_FS allocation is held over a GFP_FS | |
2460 | * allocation). | |
2461 | */ | |
2462 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { | |
2463 | if (hlock->read) { | |
2464 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) | |
2465 | return 0; | |
2466 | } else { | |
2467 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) | |
2468 | return 0; | |
2469 | } | |
2470 | } | |
2471 | ||
8e18257d PZ |
2472 | return 1; |
2473 | } | |
2474 | ||
2475 | static int separate_irq_context(struct task_struct *curr, | |
2476 | struct held_lock *hlock) | |
2477 | { | |
2478 | unsigned int depth = curr->lockdep_depth; | |
2479 | ||
2480 | /* | |
2481 | * Keep track of points where we cross into an interrupt context: | |
2482 | */ | |
2483 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + | |
2484 | curr->softirq_context; | |
2485 | if (depth) { | |
2486 | struct held_lock *prev_hlock; | |
2487 | ||
2488 | prev_hlock = curr->held_locks + depth-1; | |
2489 | /* | |
2490 | * If we cross into another context, reset the | |
2491 | * hash key (this also prevents the checking and the | |
2492 | * adding of the dependency to 'prev'): | |
2493 | */ | |
2494 | if (prev_hlock->irq_context != hlock->irq_context) | |
2495 | return 1; | |
2496 | } | |
2497 | return 0; | |
fbb9ce95 IM |
2498 | } |
2499 | ||
8e18257d | 2500 | #else |
fbb9ce95 | 2501 | |
8e18257d PZ |
2502 | static inline |
2503 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, | |
2504 | enum lock_usage_bit new_bit) | |
fbb9ce95 | 2505 | { |
8e18257d PZ |
2506 | WARN_ON(1); |
2507 | return 1; | |
2508 | } | |
fbb9ce95 | 2509 | |
8e18257d PZ |
2510 | static inline int mark_irqflags(struct task_struct *curr, |
2511 | struct held_lock *hlock) | |
2512 | { | |
2513 | return 1; | |
2514 | } | |
fbb9ce95 | 2515 | |
8e18257d PZ |
2516 | static inline int separate_irq_context(struct task_struct *curr, |
2517 | struct held_lock *hlock) | |
2518 | { | |
2519 | return 0; | |
fbb9ce95 IM |
2520 | } |
2521 | ||
868a23a8 PZ |
2522 | void lockdep_trace_alloc(gfp_t gfp_mask) |
2523 | { | |
2524 | } | |
2525 | ||
8e18257d | 2526 | #endif |
fbb9ce95 IM |
2527 | |
2528 | /* | |
8e18257d | 2529 | * Mark a lock with a usage bit, and validate the state transition: |
fbb9ce95 | 2530 | */ |
1d09daa5 | 2531 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
0764d23c | 2532 | enum lock_usage_bit new_bit) |
fbb9ce95 | 2533 | { |
8e18257d | 2534 | unsigned int new_mask = 1 << new_bit, ret = 1; |
fbb9ce95 IM |
2535 | |
2536 | /* | |
8e18257d PZ |
2537 | * If already set then do not dirty the cacheline, |
2538 | * nor do any checks: | |
fbb9ce95 | 2539 | */ |
f82b217e | 2540 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
8e18257d PZ |
2541 | return 1; |
2542 | ||
2543 | if (!graph_lock()) | |
2544 | return 0; | |
fbb9ce95 | 2545 | /* |
8e18257d | 2546 | * Make sure we didnt race: |
fbb9ce95 | 2547 | */ |
f82b217e | 2548 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
8e18257d PZ |
2549 | graph_unlock(); |
2550 | return 1; | |
2551 | } | |
fbb9ce95 | 2552 | |
f82b217e | 2553 | hlock_class(this)->usage_mask |= new_mask; |
fbb9ce95 | 2554 | |
f82b217e | 2555 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
8e18257d | 2556 | return 0; |
fbb9ce95 | 2557 | |
8e18257d | 2558 | switch (new_bit) { |
5346417e PZ |
2559 | #define LOCKDEP_STATE(__STATE) \ |
2560 | case LOCK_USED_IN_##__STATE: \ | |
2561 | case LOCK_USED_IN_##__STATE##_READ: \ | |
2562 | case LOCK_ENABLED_##__STATE: \ | |
2563 | case LOCK_ENABLED_##__STATE##_READ: | |
2564 | #include "lockdep_states.h" | |
2565 | #undef LOCKDEP_STATE | |
8e18257d PZ |
2566 | ret = mark_lock_irq(curr, this, new_bit); |
2567 | if (!ret) | |
2568 | return 0; | |
2569 | break; | |
2570 | case LOCK_USED: | |
8e18257d PZ |
2571 | debug_atomic_dec(&nr_unused_locks); |
2572 | break; | |
2573 | default: | |
2574 | if (!debug_locks_off_graph_unlock()) | |
2575 | return 0; | |
2576 | WARN_ON(1); | |
2577 | return 0; | |
2578 | } | |
fbb9ce95 | 2579 | |
8e18257d PZ |
2580 | graph_unlock(); |
2581 | ||
2582 | /* | |
2583 | * We must printk outside of the graph_lock: | |
2584 | */ | |
2585 | if (ret == 2) { | |
2586 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); | |
2587 | print_lock(this); | |
2588 | print_irqtrace_events(curr); | |
2589 | dump_stack(); | |
2590 | } | |
2591 | ||
2592 | return ret; | |
2593 | } | |
fbb9ce95 IM |
2594 | |
2595 | /* | |
2596 | * Initialize a lock instance's lock-class mapping info: | |
2597 | */ | |
2598 | void lockdep_init_map(struct lockdep_map *lock, const char *name, | |
4dfbb9d8 | 2599 | struct lock_class_key *key, int subclass) |
fbb9ce95 | 2600 | { |
c8a25005 PZ |
2601 | lock->class_cache = NULL; |
2602 | #ifdef CONFIG_LOCK_STAT | |
2603 | lock->cpu = raw_smp_processor_id(); | |
2604 | #endif | |
2605 | ||
2606 | if (DEBUG_LOCKS_WARN_ON(!name)) { | |
2607 | lock->name = "NULL"; | |
fbb9ce95 | 2608 | return; |
c8a25005 PZ |
2609 | } |
2610 | ||
2611 | lock->name = name; | |
fbb9ce95 IM |
2612 | |
2613 | if (DEBUG_LOCKS_WARN_ON(!key)) | |
2614 | return; | |
fbb9ce95 IM |
2615 | /* |
2616 | * Sanity check, the lock-class key must be persistent: | |
2617 | */ | |
2618 | if (!static_obj(key)) { | |
2619 | printk("BUG: key %p not in .data!\n", key); | |
2620 | DEBUG_LOCKS_WARN_ON(1); | |
2621 | return; | |
2622 | } | |
fbb9ce95 | 2623 | lock->key = key; |
c8a25005 PZ |
2624 | |
2625 | if (unlikely(!debug_locks)) | |
2626 | return; | |
2627 | ||
4dfbb9d8 PZ |
2628 | if (subclass) |
2629 | register_lock_class(lock, subclass, 1); | |
fbb9ce95 | 2630 | } |
fbb9ce95 IM |
2631 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
2632 | ||
2633 | /* | |
2634 | * This gets called for every mutex_lock*()/spin_lock*() operation. | |
2635 | * We maintain the dependency maps and validate the locking attempt: | |
2636 | */ | |
2637 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, | |
2638 | int trylock, int read, int check, int hardirqs_off, | |
7531e2f3 | 2639 | struct lockdep_map *nest_lock, unsigned long ip) |
fbb9ce95 IM |
2640 | { |
2641 | struct task_struct *curr = current; | |
d6d897ce | 2642 | struct lock_class *class = NULL; |
fbb9ce95 | 2643 | struct held_lock *hlock; |
fbb9ce95 IM |
2644 | unsigned int depth, id; |
2645 | int chain_head = 0; | |
2646 | u64 chain_key; | |
2647 | ||
f20786ff PZ |
2648 | if (!prove_locking) |
2649 | check = 1; | |
2650 | ||
fbb9ce95 IM |
2651 | if (unlikely(!debug_locks)) |
2652 | return 0; | |
2653 | ||
2654 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2655 | return 0; | |
2656 | ||
2657 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { | |
2658 | debug_locks_off(); | |
2659 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); | |
2660 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2661 | dump_stack(); |
fbb9ce95 IM |
2662 | return 0; |
2663 | } | |
2664 | ||
d6d897ce IM |
2665 | if (!subclass) |
2666 | class = lock->class_cache; | |
2667 | /* | |
2668 | * Not cached yet or subclass? | |
2669 | */ | |
fbb9ce95 | 2670 | if (unlikely(!class)) { |
4dfbb9d8 | 2671 | class = register_lock_class(lock, subclass, 0); |
fbb9ce95 IM |
2672 | if (!class) |
2673 | return 0; | |
2674 | } | |
2675 | debug_atomic_inc((atomic_t *)&class->ops); | |
2676 | if (very_verbose(class)) { | |
2677 | printk("\nacquire class [%p] %s", class->key, class->name); | |
2678 | if (class->name_version > 1) | |
2679 | printk("#%d", class->name_version); | |
2680 | printk("\n"); | |
2681 | dump_stack(); | |
2682 | } | |
2683 | ||
2684 | /* | |
2685 | * Add the lock to the list of currently held locks. | |
2686 | * (we dont increase the depth just yet, up until the | |
2687 | * dependency checks are done) | |
2688 | */ | |
2689 | depth = curr->lockdep_depth; | |
2690 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) | |
2691 | return 0; | |
2692 | ||
2693 | hlock = curr->held_locks + depth; | |
f82b217e DJ |
2694 | if (DEBUG_LOCKS_WARN_ON(!class)) |
2695 | return 0; | |
2696 | hlock->class_idx = class - lock_classes + 1; | |
fbb9ce95 IM |
2697 | hlock->acquire_ip = ip; |
2698 | hlock->instance = lock; | |
7531e2f3 | 2699 | hlock->nest_lock = nest_lock; |
fbb9ce95 IM |
2700 | hlock->trylock = trylock; |
2701 | hlock->read = read; | |
2702 | hlock->check = check; | |
6951b12a | 2703 | hlock->hardirqs_off = !!hardirqs_off; |
f20786ff PZ |
2704 | #ifdef CONFIG_LOCK_STAT |
2705 | hlock->waittime_stamp = 0; | |
2706 | hlock->holdtime_stamp = sched_clock(); | |
2707 | #endif | |
fbb9ce95 | 2708 | |
8e18257d PZ |
2709 | if (check == 2 && !mark_irqflags(curr, hlock)) |
2710 | return 0; | |
2711 | ||
fbb9ce95 | 2712 | /* mark it as used: */ |
4ff773bb | 2713 | if (!mark_lock(curr, hlock, LOCK_USED)) |
fbb9ce95 | 2714 | return 0; |
8e18257d | 2715 | |
fbb9ce95 | 2716 | /* |
17aacfb9 | 2717 | * Calculate the chain hash: it's the combined hash of all the |
fbb9ce95 IM |
2718 | * lock keys along the dependency chain. We save the hash value |
2719 | * at every step so that we can get the current hash easily | |
2720 | * after unlock. The chain hash is then used to cache dependency | |
2721 | * results. | |
2722 | * | |
2723 | * The 'key ID' is what is the most compact key value to drive | |
2724 | * the hash, not class->key. | |
2725 | */ | |
2726 | id = class - lock_classes; | |
2727 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) | |
2728 | return 0; | |
2729 | ||
2730 | chain_key = curr->curr_chain_key; | |
2731 | if (!depth) { | |
2732 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) | |
2733 | return 0; | |
2734 | chain_head = 1; | |
2735 | } | |
2736 | ||
2737 | hlock->prev_chain_key = chain_key; | |
8e18257d PZ |
2738 | if (separate_irq_context(curr, hlock)) { |
2739 | chain_key = 0; | |
2740 | chain_head = 1; | |
fbb9ce95 | 2741 | } |
fbb9ce95 | 2742 | chain_key = iterate_chain_key(chain_key, id); |
fbb9ce95 | 2743 | |
3aa416b0 | 2744 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
8e18257d | 2745 | return 0; |
381a2292 | 2746 | |
3aa416b0 | 2747 | curr->curr_chain_key = chain_key; |
fbb9ce95 IM |
2748 | curr->lockdep_depth++; |
2749 | check_chain_key(curr); | |
60e114d1 JP |
2750 | #ifdef CONFIG_DEBUG_LOCKDEP |
2751 | if (unlikely(!debug_locks)) | |
2752 | return 0; | |
2753 | #endif | |
fbb9ce95 IM |
2754 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
2755 | debug_locks_off(); | |
2756 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); | |
2757 | printk("turning off the locking correctness validator.\n"); | |
eedeeabd | 2758 | dump_stack(); |
fbb9ce95 IM |
2759 | return 0; |
2760 | } | |
381a2292 | 2761 | |
fbb9ce95 IM |
2762 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
2763 | max_lockdep_depth = curr->lockdep_depth; | |
2764 | ||
2765 | return 1; | |
2766 | } | |
2767 | ||
2768 | static int | |
2769 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, | |
2770 | unsigned long ip) | |
2771 | { | |
2772 | if (!debug_locks_off()) | |
2773 | return 0; | |
2774 | if (debug_locks_silent) | |
2775 | return 0; | |
2776 | ||
2777 | printk("\n=====================================\n"); | |
2778 | printk( "[ BUG: bad unlock balance detected! ]\n"); | |
2779 | printk( "-------------------------------------\n"); | |
2780 | printk("%s/%d is trying to release lock (", | |
ba25f9dc | 2781 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
2782 | print_lockdep_cache(lock); |
2783 | printk(") at:\n"); | |
2784 | print_ip_sym(ip); | |
2785 | printk("but there are no more locks to release!\n"); | |
2786 | printk("\nother info that might help us debug this:\n"); | |
2787 | lockdep_print_held_locks(curr); | |
2788 | ||
2789 | printk("\nstack backtrace:\n"); | |
2790 | dump_stack(); | |
2791 | ||
2792 | return 0; | |
2793 | } | |
2794 | ||
2795 | /* | |
2796 | * Common debugging checks for both nested and non-nested unlock: | |
2797 | */ | |
2798 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, | |
2799 | unsigned long ip) | |
2800 | { | |
2801 | if (unlikely(!debug_locks)) | |
2802 | return 0; | |
2803 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) | |
2804 | return 0; | |
2805 | ||
2806 | if (curr->lockdep_depth <= 0) | |
2807 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2808 | ||
2809 | return 1; | |
2810 | } | |
2811 | ||
64aa348e | 2812 | static int |
00ef9f73 PZ |
2813 | __lock_set_class(struct lockdep_map *lock, const char *name, |
2814 | struct lock_class_key *key, unsigned int subclass, | |
2815 | unsigned long ip) | |
64aa348e PZ |
2816 | { |
2817 | struct task_struct *curr = current; | |
2818 | struct held_lock *hlock, *prev_hlock; | |
2819 | struct lock_class *class; | |
2820 | unsigned int depth; | |
2821 | int i; | |
2822 | ||
2823 | depth = curr->lockdep_depth; | |
2824 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2825 | return 0; | |
2826 | ||
2827 | prev_hlock = NULL; | |
2828 | for (i = depth-1; i >= 0; i--) { | |
2829 | hlock = curr->held_locks + i; | |
2830 | /* | |
2831 | * We must not cross into another context: | |
2832 | */ | |
2833 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2834 | break; | |
2835 | if (hlock->instance == lock) | |
2836 | goto found_it; | |
2837 | prev_hlock = hlock; | |
2838 | } | |
2839 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2840 | ||
2841 | found_it: | |
00ef9f73 | 2842 | lockdep_init_map(lock, name, key, 0); |
64aa348e | 2843 | class = register_lock_class(lock, subclass, 0); |
f82b217e | 2844 | hlock->class_idx = class - lock_classes + 1; |
64aa348e PZ |
2845 | |
2846 | curr->lockdep_depth = i; | |
2847 | curr->curr_chain_key = hlock->prev_chain_key; | |
2848 | ||
2849 | for (; i < depth; i++) { | |
2850 | hlock = curr->held_locks + i; | |
2851 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2852 | hlock_class(hlock)->subclass, hlock->trylock, |
64aa348e | 2853 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2854 | hlock->nest_lock, hlock->acquire_ip)) |
64aa348e PZ |
2855 | return 0; |
2856 | } | |
2857 | ||
2858 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) | |
2859 | return 0; | |
2860 | return 1; | |
2861 | } | |
2862 | ||
fbb9ce95 IM |
2863 | /* |
2864 | * Remove the lock to the list of currently held locks in a | |
2865 | * potentially non-nested (out of order) manner. This is a | |
2866 | * relatively rare operation, as all the unlock APIs default | |
2867 | * to nested mode (which uses lock_release()): | |
2868 | */ | |
2869 | static int | |
2870 | lock_release_non_nested(struct task_struct *curr, | |
2871 | struct lockdep_map *lock, unsigned long ip) | |
2872 | { | |
2873 | struct held_lock *hlock, *prev_hlock; | |
2874 | unsigned int depth; | |
2875 | int i; | |
2876 | ||
2877 | /* | |
2878 | * Check whether the lock exists in the current stack | |
2879 | * of held locks: | |
2880 | */ | |
2881 | depth = curr->lockdep_depth; | |
2882 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
2883 | return 0; | |
2884 | ||
2885 | prev_hlock = NULL; | |
2886 | for (i = depth-1; i >= 0; i--) { | |
2887 | hlock = curr->held_locks + i; | |
2888 | /* | |
2889 | * We must not cross into another context: | |
2890 | */ | |
2891 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
2892 | break; | |
2893 | if (hlock->instance == lock) | |
2894 | goto found_it; | |
2895 | prev_hlock = hlock; | |
2896 | } | |
2897 | return print_unlock_inbalance_bug(curr, lock, ip); | |
2898 | ||
2899 | found_it: | |
f20786ff PZ |
2900 | lock_release_holdtime(hlock); |
2901 | ||
fbb9ce95 IM |
2902 | /* |
2903 | * We have the right lock to unlock, 'hlock' points to it. | |
2904 | * Now we remove it from the stack, and add back the other | |
2905 | * entries (if any), recalculating the hash along the way: | |
2906 | */ | |
2907 | curr->lockdep_depth = i; | |
2908 | curr->curr_chain_key = hlock->prev_chain_key; | |
2909 | ||
2910 | for (i++; i < depth; i++) { | |
2911 | hlock = curr->held_locks + i; | |
2912 | if (!__lock_acquire(hlock->instance, | |
f82b217e | 2913 | hlock_class(hlock)->subclass, hlock->trylock, |
fbb9ce95 | 2914 | hlock->read, hlock->check, hlock->hardirqs_off, |
7531e2f3 | 2915 | hlock->nest_lock, hlock->acquire_ip)) |
fbb9ce95 IM |
2916 | return 0; |
2917 | } | |
2918 | ||
2919 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) | |
2920 | return 0; | |
2921 | return 1; | |
2922 | } | |
2923 | ||
2924 | /* | |
2925 | * Remove the lock to the list of currently held locks - this gets | |
2926 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2927 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2928 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2929 | */ | |
2930 | static int lock_release_nested(struct task_struct *curr, | |
2931 | struct lockdep_map *lock, unsigned long ip) | |
2932 | { | |
2933 | struct held_lock *hlock; | |
2934 | unsigned int depth; | |
2935 | ||
2936 | /* | |
2937 | * Pop off the top of the lock stack: | |
2938 | */ | |
2939 | depth = curr->lockdep_depth - 1; | |
2940 | hlock = curr->held_locks + depth; | |
2941 | ||
2942 | /* | |
2943 | * Is the unlock non-nested: | |
2944 | */ | |
2945 | if (hlock->instance != lock) | |
2946 | return lock_release_non_nested(curr, lock, ip); | |
2947 | curr->lockdep_depth--; | |
2948 | ||
2949 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) | |
2950 | return 0; | |
2951 | ||
2952 | curr->curr_chain_key = hlock->prev_chain_key; | |
2953 | ||
f20786ff PZ |
2954 | lock_release_holdtime(hlock); |
2955 | ||
fbb9ce95 IM |
2956 | #ifdef CONFIG_DEBUG_LOCKDEP |
2957 | hlock->prev_chain_key = 0; | |
f82b217e | 2958 | hlock->class_idx = 0; |
fbb9ce95 IM |
2959 | hlock->acquire_ip = 0; |
2960 | hlock->irq_context = 0; | |
2961 | #endif | |
2962 | return 1; | |
2963 | } | |
2964 | ||
2965 | /* | |
2966 | * Remove the lock to the list of currently held locks - this gets | |
2967 | * called on mutex_unlock()/spin_unlock*() (or on a failed | |
2968 | * mutex_lock_interruptible()). This is done for unlocks that nest | |
2969 | * perfectly. (i.e. the current top of the lock-stack is unlocked) | |
2970 | */ | |
2971 | static void | |
2972 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) | |
2973 | { | |
2974 | struct task_struct *curr = current; | |
2975 | ||
2976 | if (!check_unlock(curr, lock, ip)) | |
2977 | return; | |
2978 | ||
2979 | if (nested) { | |
2980 | if (!lock_release_nested(curr, lock, ip)) | |
2981 | return; | |
2982 | } else { | |
2983 | if (!lock_release_non_nested(curr, lock, ip)) | |
2984 | return; | |
2985 | } | |
2986 | ||
2987 | check_chain_key(curr); | |
2988 | } | |
2989 | ||
2990 | /* | |
2991 | * Check whether we follow the irq-flags state precisely: | |
2992 | */ | |
1d09daa5 | 2993 | static void check_flags(unsigned long flags) |
fbb9ce95 | 2994 | { |
992860e9 IM |
2995 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
2996 | defined(CONFIG_TRACE_IRQFLAGS) | |
fbb9ce95 IM |
2997 | if (!debug_locks) |
2998 | return; | |
2999 | ||
5f9fa8a6 IM |
3000 | if (irqs_disabled_flags(flags)) { |
3001 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { | |
3002 | printk("possible reason: unannotated irqs-off.\n"); | |
3003 | } | |
3004 | } else { | |
3005 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { | |
3006 | printk("possible reason: unannotated irqs-on.\n"); | |
3007 | } | |
3008 | } | |
fbb9ce95 IM |
3009 | |
3010 | /* | |
3011 | * We dont accurately track softirq state in e.g. | |
3012 | * hardirq contexts (such as on 4KSTACKS), so only | |
3013 | * check if not in hardirq contexts: | |
3014 | */ | |
3015 | if (!hardirq_count()) { | |
3016 | if (softirq_count()) | |
3017 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); | |
3018 | else | |
3019 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); | |
3020 | } | |
3021 | ||
3022 | if (!debug_locks) | |
3023 | print_irqtrace_events(current); | |
3024 | #endif | |
3025 | } | |
3026 | ||
00ef9f73 PZ |
3027 | void lock_set_class(struct lockdep_map *lock, const char *name, |
3028 | struct lock_class_key *key, unsigned int subclass, | |
3029 | unsigned long ip) | |
64aa348e PZ |
3030 | { |
3031 | unsigned long flags; | |
3032 | ||
3033 | if (unlikely(current->lockdep_recursion)) | |
3034 | return; | |
3035 | ||
3036 | raw_local_irq_save(flags); | |
3037 | current->lockdep_recursion = 1; | |
3038 | check_flags(flags); | |
00ef9f73 | 3039 | if (__lock_set_class(lock, name, key, subclass, ip)) |
64aa348e PZ |
3040 | check_chain_key(current); |
3041 | current->lockdep_recursion = 0; | |
3042 | raw_local_irq_restore(flags); | |
3043 | } | |
00ef9f73 | 3044 | EXPORT_SYMBOL_GPL(lock_set_class); |
64aa348e | 3045 | |
fbb9ce95 IM |
3046 | /* |
3047 | * We are not always called with irqs disabled - do that here, | |
3048 | * and also avoid lockdep recursion: | |
3049 | */ | |
1d09daa5 | 3050 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
7531e2f3 PZ |
3051 | int trylock, int read, int check, |
3052 | struct lockdep_map *nest_lock, unsigned long ip) | |
fbb9ce95 IM |
3053 | { |
3054 | unsigned long flags; | |
3055 | ||
efed792d PZ |
3056 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
3057 | ||
fbb9ce95 IM |
3058 | if (unlikely(current->lockdep_recursion)) |
3059 | return; | |
3060 | ||
3061 | raw_local_irq_save(flags); | |
3062 | check_flags(flags); | |
3063 | ||
3064 | current->lockdep_recursion = 1; | |
3065 | __lock_acquire(lock, subclass, trylock, read, check, | |
7531e2f3 | 3066 | irqs_disabled_flags(flags), nest_lock, ip); |
fbb9ce95 IM |
3067 | current->lockdep_recursion = 0; |
3068 | raw_local_irq_restore(flags); | |
3069 | } | |
fbb9ce95 IM |
3070 | EXPORT_SYMBOL_GPL(lock_acquire); |
3071 | ||
1d09daa5 | 3072 | void lock_release(struct lockdep_map *lock, int nested, |
0764d23c | 3073 | unsigned long ip) |
fbb9ce95 IM |
3074 | { |
3075 | unsigned long flags; | |
3076 | ||
efed792d PZ |
3077 | trace_lock_release(lock, nested, ip); |
3078 | ||
fbb9ce95 IM |
3079 | if (unlikely(current->lockdep_recursion)) |
3080 | return; | |
3081 | ||
3082 | raw_local_irq_save(flags); | |
3083 | check_flags(flags); | |
3084 | current->lockdep_recursion = 1; | |
3085 | __lock_release(lock, nested, ip); | |
3086 | current->lockdep_recursion = 0; | |
3087 | raw_local_irq_restore(flags); | |
3088 | } | |
fbb9ce95 IM |
3089 | EXPORT_SYMBOL_GPL(lock_release); |
3090 | ||
cf40bd16 NP |
3091 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
3092 | { | |
3093 | current->lockdep_reclaim_gfp = gfp_mask; | |
3094 | } | |
3095 | ||
3096 | void lockdep_clear_current_reclaim_state(void) | |
3097 | { | |
3098 | current->lockdep_reclaim_gfp = 0; | |
3099 | } | |
3100 | ||
f20786ff PZ |
3101 | #ifdef CONFIG_LOCK_STAT |
3102 | static int | |
3103 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, | |
3104 | unsigned long ip) | |
3105 | { | |
3106 | if (!debug_locks_off()) | |
3107 | return 0; | |
3108 | if (debug_locks_silent) | |
3109 | return 0; | |
3110 | ||
3111 | printk("\n=================================\n"); | |
3112 | printk( "[ BUG: bad contention detected! ]\n"); | |
3113 | printk( "---------------------------------\n"); | |
3114 | printk("%s/%d is trying to contend lock (", | |
ba25f9dc | 3115 | curr->comm, task_pid_nr(curr)); |
f20786ff PZ |
3116 | print_lockdep_cache(lock); |
3117 | printk(") at:\n"); | |
3118 | print_ip_sym(ip); | |
3119 | printk("but there are no locks held!\n"); | |
3120 | printk("\nother info that might help us debug this:\n"); | |
3121 | lockdep_print_held_locks(curr); | |
3122 | ||
3123 | printk("\nstack backtrace:\n"); | |
3124 | dump_stack(); | |
3125 | ||
3126 | return 0; | |
3127 | } | |
3128 | ||
3129 | static void | |
3130 | __lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3131 | { | |
3132 | struct task_struct *curr = current; | |
3133 | struct held_lock *hlock, *prev_hlock; | |
3134 | struct lock_class_stats *stats; | |
3135 | unsigned int depth; | |
c7e78cff | 3136 | int i, contention_point, contending_point; |
f20786ff PZ |
3137 | |
3138 | depth = curr->lockdep_depth; | |
3139 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3140 | return; | |
3141 | ||
3142 | prev_hlock = NULL; | |
3143 | for (i = depth-1; i >= 0; i--) { | |
3144 | hlock = curr->held_locks + i; | |
3145 | /* | |
3146 | * We must not cross into another context: | |
3147 | */ | |
3148 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3149 | break; | |
3150 | if (hlock->instance == lock) | |
3151 | goto found_it; | |
3152 | prev_hlock = hlock; | |
3153 | } | |
3154 | print_lock_contention_bug(curr, lock, ip); | |
3155 | return; | |
3156 | ||
3157 | found_it: | |
3158 | hlock->waittime_stamp = sched_clock(); | |
3159 | ||
c7e78cff PZ |
3160 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
3161 | contending_point = lock_point(hlock_class(hlock)->contending_point, | |
3162 | lock->ip); | |
f20786ff | 3163 | |
f82b217e | 3164 | stats = get_lock_stats(hlock_class(hlock)); |
c7e78cff PZ |
3165 | if (contention_point < LOCKSTAT_POINTS) |
3166 | stats->contention_point[contention_point]++; | |
3167 | if (contending_point < LOCKSTAT_POINTS) | |
3168 | stats->contending_point[contending_point]++; | |
96645678 PZ |
3169 | if (lock->cpu != smp_processor_id()) |
3170 | stats->bounces[bounce_contended + !!hlock->read]++; | |
f20786ff PZ |
3171 | put_lock_stats(stats); |
3172 | } | |
3173 | ||
3174 | static void | |
c7e78cff | 3175 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3176 | { |
3177 | struct task_struct *curr = current; | |
3178 | struct held_lock *hlock, *prev_hlock; | |
3179 | struct lock_class_stats *stats; | |
3180 | unsigned int depth; | |
3181 | u64 now; | |
96645678 PZ |
3182 | s64 waittime = 0; |
3183 | int i, cpu; | |
f20786ff PZ |
3184 | |
3185 | depth = curr->lockdep_depth; | |
3186 | if (DEBUG_LOCKS_WARN_ON(!depth)) | |
3187 | return; | |
3188 | ||
3189 | prev_hlock = NULL; | |
3190 | for (i = depth-1; i >= 0; i--) { | |
3191 | hlock = curr->held_locks + i; | |
3192 | /* | |
3193 | * We must not cross into another context: | |
3194 | */ | |
3195 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) | |
3196 | break; | |
3197 | if (hlock->instance == lock) | |
3198 | goto found_it; | |
3199 | prev_hlock = hlock; | |
3200 | } | |
3201 | print_lock_contention_bug(curr, lock, _RET_IP_); | |
3202 | return; | |
3203 | ||
3204 | found_it: | |
96645678 PZ |
3205 | cpu = smp_processor_id(); |
3206 | if (hlock->waittime_stamp) { | |
3207 | now = sched_clock(); | |
3208 | waittime = now - hlock->waittime_stamp; | |
3209 | hlock->holdtime_stamp = now; | |
3210 | } | |
f20786ff | 3211 | |
2062501a FW |
3212 | trace_lock_acquired(lock, ip, waittime); |
3213 | ||
f82b217e | 3214 | stats = get_lock_stats(hlock_class(hlock)); |
96645678 PZ |
3215 | if (waittime) { |
3216 | if (hlock->read) | |
3217 | lock_time_inc(&stats->read_waittime, waittime); | |
3218 | else | |
3219 | lock_time_inc(&stats->write_waittime, waittime); | |
3220 | } | |
3221 | if (lock->cpu != cpu) | |
3222 | stats->bounces[bounce_acquired + !!hlock->read]++; | |
f20786ff | 3223 | put_lock_stats(stats); |
96645678 PZ |
3224 | |
3225 | lock->cpu = cpu; | |
c7e78cff | 3226 | lock->ip = ip; |
f20786ff PZ |
3227 | } |
3228 | ||
3229 | void lock_contended(struct lockdep_map *lock, unsigned long ip) | |
3230 | { | |
3231 | unsigned long flags; | |
3232 | ||
efed792d PZ |
3233 | trace_lock_contended(lock, ip); |
3234 | ||
f20786ff PZ |
3235 | if (unlikely(!lock_stat)) |
3236 | return; | |
3237 | ||
3238 | if (unlikely(current->lockdep_recursion)) | |
3239 | return; | |
3240 | ||
3241 | raw_local_irq_save(flags); | |
3242 | check_flags(flags); | |
3243 | current->lockdep_recursion = 1; | |
3244 | __lock_contended(lock, ip); | |
3245 | current->lockdep_recursion = 0; | |
3246 | raw_local_irq_restore(flags); | |
3247 | } | |
3248 | EXPORT_SYMBOL_GPL(lock_contended); | |
3249 | ||
c7e78cff | 3250 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
f20786ff PZ |
3251 | { |
3252 | unsigned long flags; | |
3253 | ||
3254 | if (unlikely(!lock_stat)) | |
3255 | return; | |
3256 | ||
3257 | if (unlikely(current->lockdep_recursion)) | |
3258 | return; | |
3259 | ||
3260 | raw_local_irq_save(flags); | |
3261 | check_flags(flags); | |
3262 | current->lockdep_recursion = 1; | |
c7e78cff | 3263 | __lock_acquired(lock, ip); |
f20786ff PZ |
3264 | current->lockdep_recursion = 0; |
3265 | raw_local_irq_restore(flags); | |
3266 | } | |
3267 | EXPORT_SYMBOL_GPL(lock_acquired); | |
3268 | #endif | |
3269 | ||
fbb9ce95 IM |
3270 | /* |
3271 | * Used by the testsuite, sanitize the validator state | |
3272 | * after a simulated failure: | |
3273 | */ | |
3274 | ||
3275 | void lockdep_reset(void) | |
3276 | { | |
3277 | unsigned long flags; | |
23d95a03 | 3278 | int i; |
fbb9ce95 IM |
3279 | |
3280 | raw_local_irq_save(flags); | |
3281 | current->curr_chain_key = 0; | |
3282 | current->lockdep_depth = 0; | |
3283 | current->lockdep_recursion = 0; | |
3284 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); | |
3285 | nr_hardirq_chains = 0; | |
3286 | nr_softirq_chains = 0; | |
3287 | nr_process_chains = 0; | |
3288 | debug_locks = 1; | |
23d95a03 IM |
3289 | for (i = 0; i < CHAINHASH_SIZE; i++) |
3290 | INIT_LIST_HEAD(chainhash_table + i); | |
fbb9ce95 IM |
3291 | raw_local_irq_restore(flags); |
3292 | } | |
3293 | ||
3294 | static void zap_class(struct lock_class *class) | |
3295 | { | |
3296 | int i; | |
3297 | ||
3298 | /* | |
3299 | * Remove all dependencies this lock is | |
3300 | * involved in: | |
3301 | */ | |
3302 | for (i = 0; i < nr_list_entries; i++) { | |
3303 | if (list_entries[i].class == class) | |
3304 | list_del_rcu(&list_entries[i].entry); | |
3305 | } | |
3306 | /* | |
3307 | * Unhash the class and remove it from the all_lock_classes list: | |
3308 | */ | |
3309 | list_del_rcu(&class->hash_entry); | |
3310 | list_del_rcu(&class->lock_entry); | |
3311 | ||
8bfe0298 | 3312 | class->key = NULL; |
fbb9ce95 IM |
3313 | } |
3314 | ||
fabe874a | 3315 | static inline int within(const void *addr, void *start, unsigned long size) |
fbb9ce95 IM |
3316 | { |
3317 | return addr >= start && addr < start + size; | |
3318 | } | |
3319 | ||
3320 | void lockdep_free_key_range(void *start, unsigned long size) | |
3321 | { | |
3322 | struct lock_class *class, *next; | |
3323 | struct list_head *head; | |
3324 | unsigned long flags; | |
3325 | int i; | |
5a26db5b | 3326 | int locked; |
fbb9ce95 IM |
3327 | |
3328 | raw_local_irq_save(flags); | |
5a26db5b | 3329 | locked = graph_lock(); |
fbb9ce95 IM |
3330 | |
3331 | /* | |
3332 | * Unhash all classes that were created by this module: | |
3333 | */ | |
3334 | for (i = 0; i < CLASSHASH_SIZE; i++) { | |
3335 | head = classhash_table + i; | |
3336 | if (list_empty(head)) | |
3337 | continue; | |
fabe874a | 3338 | list_for_each_entry_safe(class, next, head, hash_entry) { |
fbb9ce95 IM |
3339 | if (within(class->key, start, size)) |
3340 | zap_class(class); | |
fabe874a AV |
3341 | else if (within(class->name, start, size)) |
3342 | zap_class(class); | |
3343 | } | |
fbb9ce95 IM |
3344 | } |
3345 | ||
5a26db5b NP |
3346 | if (locked) |
3347 | graph_unlock(); | |
fbb9ce95 IM |
3348 | raw_local_irq_restore(flags); |
3349 | } | |
3350 | ||
3351 | void lockdep_reset_lock(struct lockdep_map *lock) | |
3352 | { | |
d6d897ce | 3353 | struct lock_class *class, *next; |
fbb9ce95 IM |
3354 | struct list_head *head; |
3355 | unsigned long flags; | |
3356 | int i, j; | |
5a26db5b | 3357 | int locked; |
fbb9ce95 IM |
3358 | |
3359 | raw_local_irq_save(flags); | |
fbb9ce95 IM |
3360 | |
3361 | /* | |
d6d897ce IM |
3362 | * Remove all classes this lock might have: |
3363 | */ | |
3364 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { | |
3365 | /* | |
3366 | * If the class exists we look it up and zap it: | |
3367 | */ | |
3368 | class = look_up_lock_class(lock, j); | |
3369 | if (class) | |
3370 | zap_class(class); | |
3371 | } | |
3372 | /* | |
3373 | * Debug check: in the end all mapped classes should | |
3374 | * be gone. | |
fbb9ce95 | 3375 | */ |
5a26db5b | 3376 | locked = graph_lock(); |
fbb9ce95 IM |
3377 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
3378 | head = classhash_table + i; | |
3379 | if (list_empty(head)) | |
3380 | continue; | |
3381 | list_for_each_entry_safe(class, next, head, hash_entry) { | |
d6d897ce | 3382 | if (unlikely(class == lock->class_cache)) { |
74c383f1 IM |
3383 | if (debug_locks_off_graph_unlock()) |
3384 | WARN_ON(1); | |
d6d897ce | 3385 | goto out_restore; |
fbb9ce95 IM |
3386 | } |
3387 | } | |
3388 | } | |
5a26db5b NP |
3389 | if (locked) |
3390 | graph_unlock(); | |
d6d897ce IM |
3391 | |
3392 | out_restore: | |
fbb9ce95 IM |
3393 | raw_local_irq_restore(flags); |
3394 | } | |
3395 | ||
1499993c | 3396 | void lockdep_init(void) |
fbb9ce95 IM |
3397 | { |
3398 | int i; | |
3399 | ||
3400 | /* | |
3401 | * Some architectures have their own start_kernel() | |
3402 | * code which calls lockdep_init(), while we also | |
3403 | * call lockdep_init() from the start_kernel() itself, | |
3404 | * and we want to initialize the hashes only once: | |
3405 | */ | |
3406 | if (lockdep_initialized) | |
3407 | return; | |
3408 | ||
3409 | for (i = 0; i < CLASSHASH_SIZE; i++) | |
3410 | INIT_LIST_HEAD(classhash_table + i); | |
3411 | ||
3412 | for (i = 0; i < CHAINHASH_SIZE; i++) | |
3413 | INIT_LIST_HEAD(chainhash_table + i); | |
3414 | ||
3415 | lockdep_initialized = 1; | |
3416 | } | |
3417 | ||
3418 | void __init lockdep_info(void) | |
3419 | { | |
3420 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); | |
3421 | ||
b0788caf | 3422 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
fbb9ce95 IM |
3423 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
3424 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); | |
b0788caf | 3425 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
fbb9ce95 IM |
3426 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
3427 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); | |
3428 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); | |
3429 | ||
3430 | printk(" memory used by lock dependency info: %lu kB\n", | |
3431 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + | |
3432 | sizeof(struct list_head) * CLASSHASH_SIZE + | |
3433 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + | |
3434 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + | |
3435 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); | |
3436 | ||
3437 | printk(" per task-struct memory footprint: %lu bytes\n", | |
3438 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); | |
3439 | ||
3440 | #ifdef CONFIG_DEBUG_LOCKDEP | |
c71063c9 JB |
3441 | if (lockdep_init_error) { |
3442 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); | |
3443 | printk("Call stack leading to lockdep invocation was:\n"); | |
3444 | print_stack_trace(&lockdep_init_trace, 0); | |
3445 | } | |
fbb9ce95 IM |
3446 | #endif |
3447 | } | |
3448 | ||
fbb9ce95 IM |
3449 | static void |
3450 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, | |
55794a41 | 3451 | const void *mem_to, struct held_lock *hlock) |
fbb9ce95 IM |
3452 | { |
3453 | if (!debug_locks_off()) | |
3454 | return; | |
3455 | if (debug_locks_silent) | |
3456 | return; | |
3457 | ||
3458 | printk("\n=========================\n"); | |
3459 | printk( "[ BUG: held lock freed! ]\n"); | |
3460 | printk( "-------------------------\n"); | |
3461 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", | |
ba25f9dc | 3462 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
55794a41 | 3463 | print_lock(hlock); |
fbb9ce95 IM |
3464 | lockdep_print_held_locks(curr); |
3465 | ||
3466 | printk("\nstack backtrace:\n"); | |
3467 | dump_stack(); | |
3468 | } | |
3469 | ||
54561783 ON |
3470 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
3471 | const void* lock_from, unsigned long lock_len) | |
3472 | { | |
3473 | return lock_from + lock_len <= mem_from || | |
3474 | mem_from + mem_len <= lock_from; | |
3475 | } | |
3476 | ||
fbb9ce95 IM |
3477 | /* |
3478 | * Called when kernel memory is freed (or unmapped), or if a lock | |
3479 | * is destroyed or reinitialized - this code checks whether there is | |
3480 | * any held lock in the memory range of <from> to <to>: | |
3481 | */ | |
3482 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) | |
3483 | { | |
fbb9ce95 IM |
3484 | struct task_struct *curr = current; |
3485 | struct held_lock *hlock; | |
3486 | unsigned long flags; | |
3487 | int i; | |
3488 | ||
3489 | if (unlikely(!debug_locks)) | |
3490 | return; | |
3491 | ||
3492 | local_irq_save(flags); | |
3493 | for (i = 0; i < curr->lockdep_depth; i++) { | |
3494 | hlock = curr->held_locks + i; | |
3495 | ||
54561783 ON |
3496 | if (not_in_range(mem_from, mem_len, hlock->instance, |
3497 | sizeof(*hlock->instance))) | |
fbb9ce95 IM |
3498 | continue; |
3499 | ||
54561783 | 3500 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
fbb9ce95 IM |
3501 | break; |
3502 | } | |
3503 | local_irq_restore(flags); | |
3504 | } | |
ed07536e | 3505 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
fbb9ce95 IM |
3506 | |
3507 | static void print_held_locks_bug(struct task_struct *curr) | |
3508 | { | |
3509 | if (!debug_locks_off()) | |
3510 | return; | |
3511 | if (debug_locks_silent) | |
3512 | return; | |
3513 | ||
3514 | printk("\n=====================================\n"); | |
3515 | printk( "[ BUG: lock held at task exit time! ]\n"); | |
3516 | printk( "-------------------------------------\n"); | |
3517 | printk("%s/%d is exiting with locks still held!\n", | |
ba25f9dc | 3518 | curr->comm, task_pid_nr(curr)); |
fbb9ce95 IM |
3519 | lockdep_print_held_locks(curr); |
3520 | ||
3521 | printk("\nstack backtrace:\n"); | |
3522 | dump_stack(); | |
3523 | } | |
3524 | ||
3525 | void debug_check_no_locks_held(struct task_struct *task) | |
3526 | { | |
3527 | if (unlikely(task->lockdep_depth > 0)) | |
3528 | print_held_locks_bug(task); | |
3529 | } | |
3530 | ||
3531 | void debug_show_all_locks(void) | |
3532 | { | |
3533 | struct task_struct *g, *p; | |
3534 | int count = 10; | |
3535 | int unlock = 1; | |
3536 | ||
9c35dd7f JP |
3537 | if (unlikely(!debug_locks)) { |
3538 | printk("INFO: lockdep is turned off.\n"); | |
3539 | return; | |
3540 | } | |
fbb9ce95 IM |
3541 | printk("\nShowing all locks held in the system:\n"); |
3542 | ||
3543 | /* | |
3544 | * Here we try to get the tasklist_lock as hard as possible, | |
3545 | * if not successful after 2 seconds we ignore it (but keep | |
3546 | * trying). This is to enable a debug printout even if a | |
3547 | * tasklist_lock-holding task deadlocks or crashes. | |
3548 | */ | |
3549 | retry: | |
3550 | if (!read_trylock(&tasklist_lock)) { | |
3551 | if (count == 10) | |
3552 | printk("hm, tasklist_lock locked, retrying... "); | |
3553 | if (count) { | |
3554 | count--; | |
3555 | printk(" #%d", 10-count); | |
3556 | mdelay(200); | |
3557 | goto retry; | |
3558 | } | |
3559 | printk(" ignoring it.\n"); | |
3560 | unlock = 0; | |
46fec7ac | 3561 | } else { |
3562 | if (count != 10) | |
3563 | printk(KERN_CONT " locked it.\n"); | |
fbb9ce95 | 3564 | } |
fbb9ce95 IM |
3565 | |
3566 | do_each_thread(g, p) { | |
85684873 IM |
3567 | /* |
3568 | * It's not reliable to print a task's held locks | |
3569 | * if it's not sleeping (or if it's not the current | |
3570 | * task): | |
3571 | */ | |
3572 | if (p->state == TASK_RUNNING && p != current) | |
3573 | continue; | |
fbb9ce95 IM |
3574 | if (p->lockdep_depth) |
3575 | lockdep_print_held_locks(p); | |
3576 | if (!unlock) | |
3577 | if (read_trylock(&tasklist_lock)) | |
3578 | unlock = 1; | |
3579 | } while_each_thread(g, p); | |
3580 | ||
3581 | printk("\n"); | |
3582 | printk("=============================================\n\n"); | |
3583 | ||
3584 | if (unlock) | |
3585 | read_unlock(&tasklist_lock); | |
3586 | } | |
fbb9ce95 IM |
3587 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
3588 | ||
82a1fcb9 IM |
3589 | /* |
3590 | * Careful: only use this function if you are sure that | |
3591 | * the task cannot run in parallel! | |
3592 | */ | |
3593 | void __debug_show_held_locks(struct task_struct *task) | |
fbb9ce95 | 3594 | { |
9c35dd7f JP |
3595 | if (unlikely(!debug_locks)) { |
3596 | printk("INFO: lockdep is turned off.\n"); | |
3597 | return; | |
3598 | } | |
fbb9ce95 IM |
3599 | lockdep_print_held_locks(task); |
3600 | } | |
82a1fcb9 IM |
3601 | EXPORT_SYMBOL_GPL(__debug_show_held_locks); |
3602 | ||
3603 | void debug_show_held_locks(struct task_struct *task) | |
3604 | { | |
3605 | __debug_show_held_locks(task); | |
3606 | } | |
fbb9ce95 | 3607 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
b351d164 PZ |
3608 | |
3609 | void lockdep_sys_exit(void) | |
3610 | { | |
3611 | struct task_struct *curr = current; | |
3612 | ||
3613 | if (unlikely(curr->lockdep_depth)) { | |
3614 | if (!debug_locks_off()) | |
3615 | return; | |
3616 | printk("\n================================================\n"); | |
3617 | printk( "[ BUG: lock held when returning to user space! ]\n"); | |
3618 | printk( "------------------------------------------------\n"); | |
3619 | printk("%s/%d is leaving the kernel with locks still held!\n", | |
3620 | curr->comm, curr->pid); | |
3621 | lockdep_print_held_locks(curr); | |
3622 | } | |
3623 | } |